Beijing on Thursday brushed off the United States' threats of sanctions on countries that buy Iranian oil."China opposes illegal unilateral sanctions without authorization of the United Nations Security Council," Foreign Ministry spokesperson Guo Jiakun told reporters during the ministry's regular press briefing.The remarks came after U.S. Treasury Secretary Scott Bessent said Washington was prepared to impose secondary sanctions over purchases of Iranian oil, describing the move as the "financial equivalent" of the weeks of U.S. and Israeli military strikes on Iran before a temporary ceasefire was reached last week."We believe this blockade in the straits—there will be a pause of Chinese buying—but I will tell you that two Chinese banks received letters from the U.S. Treasury...we told them that if we can prove that there's Iranian money flowing through your accounts then we are willing to put on secondary sanctions," he told reporters, without identifying the banks.Newsweek reached out to the Chinese embassy in the U.S. and Iran's Foreign Ministry via email for comment.The sanctions threat, alongside the U.S. blockade that began Monday, is part of a maximalist campaign to squeeze Iran’s oil revenues—a central pillar of its economy—and pressure Tehran in ongoing negotiations. The first round of U.S.-Iran talks in Pakistan ended without agreement on Sunday, with both sides signaling gaps remained over core issues, including limits on Iran’s nuclear program and sanctions relief.The blockade further restricts traffic through the Strait of Hormuz, a key conduit for roughly one-quarter of global seaborne oil and one-fifth of liquefied natural gas, after nearly seven weeks of disruption caused by Iran’s closure of the waterway in response to U.S. and Israeli attacks. No vessels have breached the blockade, and all 10 vessels that attempted to were turned back, the U.S. military’s Central Command said Wednesday.The world's second-largest economy has a strong interest in keeping the waterway open and energy flows stable.While Beijing does not officially purchase sanctioned Iranian oil, it remains the destination for more than 80 percent of Iran’s crude exports, according to analytics firm Kpler. Iranian oil accounted for about 13.4 percent of China’s roughly 10.27 million barrels per day of seaborne imports, typically shipped via so-called “shadow fleet” vessels and offloaded onto other vessels for transfer to Chinese refineries.Treasury Secretary Scott Bessent speaks to reporters at the White House on April 15, 2026. | Manuel Balce Ceneta/AP"Beijing has built a layered evasion architecture that protects sanctioned oil trade at the two points where Western enforcement is designed to bite hardest: the origin of the cargo and the settlement of value," the House of Representatives' House Select Committee on the Chinese Communist Party wrote in a March report.Although China is less exposed to the shock than many of its neighbors due to its investments in ren