Trump Warns China of Consequences Over Iran Arms Support Ahead of Xi Summit

U.S. intelligence agencies believe China is preparing to ship shoulder-fired anti-aircraft missiles to Iran through third-country intermediaries — an allegation Beijing flatly denies — and the dispute has upended preparations for what was supposed to be a trade-focused summit between President Donald Trump and Chinese President Xi Jinping next month [1].

Trump responded over the weekend with an escalating series of threats. "If China does that, China is gonna have big problems," he told reporters on Saturday while departing the White House [2]. By Sunday morning, he was more specific: a 50% tariff on all Chinese imports, with no exemptions, for any country that supplies weapons to Iran [3]. The timing is not accidental. The threats arrive five weeks before Trump is scheduled to travel to Beijing for a May 14-15 summit with Xi [4], and amid a fragile ceasefire in the U.S.-Iran conflict that China itself helped broker [5].

The question now is whether Washington's public pressure campaign will curtail Chinese military support for Tehran, or whether it will poison the summit before it starts.

The Intelligence Behind the Accusation

CNN reported on April 11, citing three people familiar with recent intelligence assessments, that Beijing is preparing to transfer man-portable air-defense systems (MANPADs) — shoulder-fired missiles designed to shoot down low-flying aircraft and helicopters — to Iran within weeks [1]. U.S. officials say the shipments are being routed through third countries to obscure their origin.

A spokesperson for the Chinese Embassy in Washington issued a categorical denial: "China has never provided weapons to any party to the conflict; the information in question is untrue" [6].

The accusation fits a pattern that U.S. agencies have documented for years. In October 2025, ten China-based entities were added to the Commerce Department's Entity List after U.S.-origin electronic components were recovered from the debris of weaponized drones operated by Iranian proxy groups, including Houthi militants, in attacks dating back to 2017 [7]. The Atlantic Council has documented a broader shift in China's military support for Iran, moving from direct arms sales in earlier decades to harder-to-trace dual-use technology transfers — sensors, navigation systems, electronic components, and rocket fuel precursors [8].

In March 2026, the U.S. accused Semiconductor Manufacturing International Corporation (SMIC), China's largest chipmaker, of providing chipmaking tools to Iran's military [18]. Earlier, in May 2025, the State Department sanctioned entities primarily based in China and Hong Kong for supporting Iran's ballistic missile program [16].

A Decades-Long Supply Chain

The China-Iran military relationship is not new. Chinese companies have faced U.S. sanctions for proliferation activities related to Iran since at least 2002. What has changed is the scale of U.S. enforcement and the breadth of the commercial ties under scrutiny.

Source: CNAS / U.S. Treasury OFAC

Data as of Mar 1, 2026CSV

In 2025 alone, more than 230 Chinese individuals and organizations were designated under the Treasury Department's OFAC sanctions programs related to Iran, Russia, and North Korea [9]. The Commerce Department's Bureau of Industry and Security added 23 Chinese companies to its Entity List in a single action in September 2025, focused on firms facilitating technology diversion to Iran and Russia [19].

The first Trump administration sanctioned 45 Chinese entities for violating secondary sanctions on Iran during its "maximum pressure" campaign from 2018 to 2020 [9]. But the second Trump administration has escalated sharply: the 2025 designation total of 45 entities matched the entire first-term count in a single year.

Specific companies that have drawn enforcement action include Shandong Shouguang Luqing Petrochemical, a privately owned refinery in Shandong province that the Treasury Department sanctioned in March 2025 for purchasing approximately half a billion dollars worth of Iranian crude oil [10]. It was the first time a Chinese "teapot" refinery — an industry term for small, independent refiners — had been directly targeted. Five other Shandong refineries reportedly stopped buying Iranian crude afterward, fearing they would be next [10].

Iran's Economic Lifeline from China

Tehran's dependence on Chinese economic support is difficult to overstate. China purchased more than 80% of Iran's oil exports in 2025, roughly 1.38 million barrels per day, representing 13-14% of China's total seaborne crude imports [11]. Iranian crude trades at a discount of $8-$10 per barrel below global benchmarks, making it financially attractive to the Shandong teapot refineries that serve as its primary buyers.

Source: UN COMTRADE / OEC World

Data as of Jan 15, 2026CSV

China-Iran bilateral trade peaked at $43 billion in 2015, collapsed to roughly $18 billion by 2020 under the combined pressure of low oil prices and the first Trump administration's maximum pressure sanctions, then partially recovered to $38 billion in 2022 before falling again. The 2026 war in Iran has severely disrupted trade flows, with Iranian crude production and infrastructure suffering extensive damage since the U.S.-Israeli air campaign began in late February.

The 25-year Comprehensive Strategic Partnership signed in March 2021 envisions $400 billion in Chinese investment in Iran — $280 billion for oil, gas, and petrochemical development, and $120 billion for transportation and manufacturing infrastructure [15]. Implementation has lagged far behind those headline figures, with Chinese state-owned enterprises cautious about exposure to U.S. sanctions. But the agreement signals the depth of the strategic alignment.

The Consequences Trump Has Threatened

The administration's threatened response has two main components. The first is tariffs: Trump's 50% levy threat on all Chinese imports would represent a major escalation even in the context of an already punishing trade war [3]. The second is the broader suite of secondary sanctions that the Treasury Department has been expanding since early 2025.

Secondary sanctions target not the sanctioned country directly but third parties that do business with it — in this case, Chinese firms and financial institutions that facilitate Iranian transactions. The threat is exclusion from the U.S. financial system, which remains the backbone of global dollar-denominated trade.

The question of effectiveness is contested. The March 2025 sanctions against Shouguang Luqing Petrochemical did cause a temporary pullback among Shandong refineries [10]. But the broader flow of Iranian oil to China has proven resilient. As analysts at Radio Free Europe noted, "U.S. sanctions are unlikely to have an impact on Iranian oil flowing to China unless the White House targets Beijing's state-owned enterprises and infrastructure" — a step that would carry enormous economic costs for both sides.

Trump's first-term maximum pressure campaign offers a mixed precedent. It succeeded in driving Iran's oil exports and bilateral trade with China down substantially between 2018 and 2020. But it did not end the relationship. Chinese purchases of Iranian crude continued through shadow fleets and transshipment networks, and technology transfers persisted through front companies.

Chinese Components on the Battlefield

The military dimension of the China-Iran relationship has taken on new urgency since the 2026 conflict began. Analysts at Modern Diplomacy have argued that by supplying Iran with drone technology and integrating Chinese components into Iranian weapons systems, Beijing gains real-world performance data on how its military technology holds up against Western defense systems like the Patriot missile battery [18].

The documented record includes Chinese-origin components found in Houthi drone attacks on U.S. forces and commercial shipping, a pattern that led to the October 2025 Entity List additions [7]. The CENTCOM commander's nominee testified to Congress that Iranian proxies continue to threaten U.S. troops, with weapons systems that rely in part on Chinese-supplied sensors and electronic components [7].

If the latest intelligence is accurate, the proposed MANPAD shipment would represent a qualitative shift — from components embedded in Iranian-manufactured systems to complete Chinese weapon systems transferring to an active combatant. That distinction matters both militarily and diplomatically.

The Case That Pressure Is Counterproductive

Not all analysts agree that public ultimatums ahead of a summit serve U.S. interests. The Brookings Institution argued that "by conditioning the Trump visit on Chinese cooperation in a U.S.-initiated military crisis, Trump converted a manageable scheduling adjustment into a forced binary: comply or refuse" [12]. The framing, Brookings analysts wrote, makes any cooperation look like submission to American pressure — the one outcome Beijing's domestic politics cannot tolerate.

Li Haidong of China Foreign Affairs University told the Global Times that the U.S. approach "reflects attempts to shift responsibility for the U.S.-Israel conflict onto Beijing" [13]. Liu Zhongmin of Shanghai International Studies University argued that Washington was trying to "drag more countries into the issue" [13]. These views are not confined to Chinese state-affiliated commentators; some Western China scholars share the assessment that public confrontation before summits tends to produce theatrical defiance rather than quiet concessions.

The South China Morning Post reported that Chinese experts believe "the United States is undermining itself, so they just need to get out of the way" [13]. The historical record offers some support for this view: Beijing's most significant diplomatic concessions — including its role in brokering the current Iran ceasefire alongside Pakistan in late March [17] — have tended to come through back-channel engagement rather than public pressure.

The Diplomat noted that "the United States and China need to lower expectations about Trump's trip and focus on delivering a few concrete outcomes" [14]. A summit derailed by mutual recrimination over Iran would leave trade issues — tariffs, rare earth export controls, fentanyl enforcement — unresolved as well.

What Both Sides Want From the Summit

The May summit was originally designed around trade. After the Busan agreement earlier this year, where Trump and Xi agreed to a trade truce involving scaled-back tariffs, resumed soybean purchases, and a pause on Chinese rare earth export curbs [20], Beijing and Washington were laying groundwork for a more comprehensive economic framework.

Iran has now intruded onto the agenda. The administration has signaled it wants Xi to commit to three things: halting weapons transfers to Iran, supporting enforcement of the ceasefire, and helping reopen the Strait of Hormuz to normal commercial shipping [5][17]. China and Pakistan's five-point proposal from March 31 already calls for a ceasefire and resumed navigation in the strait [17], but the U.S. wants Beijing to act as a guarantor — a role Chinese officials have resisted.

For Xi, the priority remains Taiwan. Beijing consistently seeks U.S. commitments to constrain arms sales to Taiwan and limit the scope of U.S.-Taiwan diplomatic relations [20]. Fentanyl enforcement, where China agreed at Busan to target illicit trafficking, remains an ongoing demand from the U.S. side.

The domestic political constraints on both leaders are real. Trump faces pressure from hawkish members of Congress and defense establishment figures who view any engagement with Beijing as weakness on Iran. Xi faces a nationalist constituency that recoils at any appearance of yielding to American coercion, particularly when the framing involves choosing between the U.S. and a longstanding strategic partner in Tehran.

The Ceasefire in the Balance

The immediate backdrop to this confrontation is the fragile ceasefire that took effect on April 8, brokered by Pakistan with Chinese diplomatic support [5][17]. Iran had restricted shipping through the Strait of Hormuz during the conflict, reducing oil transit by more than 90% — roughly 10 million barrels per day — and imposing tolls exceeding $1 million per ship [17]. Vice President Vance left Pakistan on April 12 after negotiations failed to produce an agreement on fully reopening the strait.

China has substantial self-interest in resolving the Hormuz crisis: it imports significant volumes of oil through the waterway, and global energy price spikes triggered by the closure have hit Chinese manufacturers. But Beijing has also shown reluctance to be drawn deeper into an enforcement role in a conflict it did not initiate.

The weapons shipment allegation complicates that balancing act. If China is simultaneously brokering a ceasefire and arming one of the combatants, the credibility of its mediator role collapses. If the intelligence is wrong or exaggerated — as Beijing insists — then the public accusation poisons the diplomatic atmosphere for no gain.

What Comes Next

Five weeks remain before the scheduled summit. The Trump administration's strategy appears to be using the weapons intelligence as leverage — raising the cost to Beijing of continuing military support for Iran while the ceasefire remains tenuous and the Hormuz crisis unresolved. The risk is that the leverage turns into an ultimatum, and ultimatums directed at Beijing have a track record of producing resistance rather than compliance.

The sanctions infrastructure is already in place. The Entity List is expanding, teapot refineries are being targeted, and the 50% tariff threat looms. Whether these tools produce a Chinese course correction on Iran — or simply add another layer of friction to the world's most consequential bilateral relationship — will depend on whether the back-channel diplomacy is more productive than the public rhetoric suggests.