US President Donald Trump said on Wednesday that the memorandum of understanding signed with Iran to end the conflict was "over", adding he did not want to engage with Tehran, calling the Iranian leadership "sick people".

Speaking at a summit of NATO leaders in Ankara, Trump also said he had ordered his Treasury Secretary Scott Bessent to cut off trade ties with Spain, calling Madrid a "terrible partner" in NATO.

The twin announcements overshadowed a summit that European leaders hoped would be focused on projecting unity and support for Ukraine, and put a lid on a series of rows that have threatened to blow NATO apart.

The US unleashed new military strikes on Iran and revoked a license allowing Iran to sell oil in response to attacks on three tankers. It was the latest blow to a fragile ceasefire agreement in a war that is deeply unpopular in Europe.

"It's a very interesting question. To me, I think it's over. I don't want to deal with them," Trump said when asked whether the interim accord with Iran that envisaged hammering out a long-term peace deal by mid-August was over. "They're scum. They're sick people. They're led by sick people."

"As far as I'm concerned, it's just a waste of time dealing with them," he said.

Washington and Madrid have been at loggerheads, with Spain explicitly rejecting Trump's demands for European countries to sharply increase military spending to pay for their own defence.

"Spain is a wasted cause. We don't want to do any trade business with Spain anymore," Trump said. "By the way, I'd like to cut it off. Spain is a terrible partner in NATO. They don't participate, they don't pay. I don't want anything to do with Spain. Cut off all trade with Spain, including visits."

In response, the office of Prime Minister Pedro Sanchez said it was treating Trump's statements as business as usual, adding that bilateral relations benefited both countries.