The United States yesterday announced new sanctions to stop Iran from selling its oil, casting a cloud over last-minute European efforts to arrange a tension-reducing encounter between the adversaries’ presidents. French President Emmanuel Macron shuttled between his US and Iranian counterparts over two days at the United Nations, but acknowledged that time was running short.

On US President Donald Trump’s last scheduled day at the annual UN summit of world leaders, his administration said it was imposing sanctions on Chinese companies that have purchased Iranian oil. “We’re telling China, and all nations—know that we will sanction every violation of sanctions of all activity,” Secretary of State Mike Pompeo told a pressure group opposed to Iran’s clerical regime on the sidelines of the United Nations.

China, which is embroiled in a series of disputes with the United States including a trade war, is believed to be the biggest foreign buyer of Iranian oil. The Trump administration in May said that the United States would unilaterally force all countries to stop buying Iran’s oil, its major export, sending tensions soaring. The United States blamed Iran for an attack earlier this month on the oil infrastructure of rival Saudi Arabia, which is also waging a devastating offensive in Yemen.

France, Britain and Germany this week said they agreed with the US findings. “Some have said that they’ve joined the United States; I think they have joined reality,” Pompeo said of the Europeans.