China has criticized US sanctions on Iran and threats of penalties for Tehran's economic partners, vowing to protect its interests and warning Washington not to “interfere” with its trade with Iran.What happened: Foreign Ministry spokesperson Lin Jian said in a news briefing on Tuesday that China was firmly opposed to what it called “illegal unilateral sanctions” and would take “all necessary measures” to safeguard its rights.“Cooperation between China and Iran has always been conducted within the framework of international law and should not be interfered with or disrupted,” Lin said.“China has already stated many times that it firmly opposes illegal unilateral sanctions. China will take all necessary measures to firmly safeguard its own rights and interests," he added.Lin said that an economic war will not help resolve the Iran conflict.“They will only further intensify contradictions and conflicts, cause risks to spill over, disrupt the global economic and financial order and harm the legitimate rights and interests of other countries," Lin added.Meanwhile, Tehran on Tuesday vowed to resist the widening US sanctions."The enemies should wait for an attack," Iranian Economy Minister Ali Madanizadeh told state television. Neither China nor Russia ‌had "accepted" the secondary sanctions, he noted, predicting that other countries would resist them.US Treasury Secretary Scott Bessent announced severe new sanctions on Monday, warning that any country trading with Iran would be isolated. Among them were new designations on 60 individuals, entities and vessels, but did not include the Chinese institutions Washington suspects are facilitating Tehran’s oil trade.Why it matters: China is a key trade partner to Iran and is the biggest buyer of Iranian crude, taking more than 90% of shipments from the Islamic Republic, mainly through shadow fleets. However, a blockade on Iranian ports imposed by the US since April has drastically decreased those flows. Iranian oil exports to China fell to 785,000 barrels ​per day in June, the lowest since ​February 2023, Kpler data showed on Aug. 21.Iran has seen its economy devastated as a result of the war, blockade and current sanctions on the country since the conflict with the US and Israel began on Feb. 28. The Iranian rial fell to a record low of 2.02 million to the dollar on Monday.In Washington, Bessent described the initial measures as a “warning shot.” The sanctions were announced ahead of Trump’s expected meeting with Chinese President Xi Jinping in Washington next month, where trade tensions and access to critical minerals are expected to feature prominently.“Why would I want to blow up the global financial system?” Bessent said when asked why the measures weren’t more severe."We want to make clear here today that no one is above the reach of US sanctions," the Treasury Secretary said in response to a question ⁠about Chinese banks.Know more: Brent crude oil, the international benchmark, was down 3.72% to $88.72 a barrel as of 12:00 p.m. EDT.