Spain's left-wing government led by Prime Minister Pedro Sanchez, one of Europe's most defiant leaders against Trump, has said that bases long used by US forces could only be allowed for activities consistent with the United Nations Charter.

"Spain has been terrible," Trump told reporters as he met German Chancellor Friedrich Merz at the White House.

He also pointed to Sanchez's refusal to join NATO allies in a pledge to boost defense spending to five percent of GDP, a level pushed by Trump who says the United States bears too much of a burden.

"So we're going to cut off all trade with Spain. We don't want anything to do with Spain," Trump said, adding that he had asked Treasury Secretary Scott Bessent to "cut off all dealings with Spain."

It remains unclear what power Trump would have to "end" trade with Spain, after the Supreme Court struck down his use of emergency powers to impose arbitrary tariffs.

Musing on the legalities, the 79-year-old property tycoon turned president said, "I could tomorrow stop -- or today, even better -- stop everything having to do with Spain, all business."

"I have the right to... do anything I want with it," he said.

The Spanish government quickly responded that it had a "mutually beneficial" trading relationship with the United States and other countries.

"If the US administration wishes to review this relationship, it must do so while respecting the autonomy of private companies, international law and bilateral agreements between the European Union and the US," it said.

"Our country has the necessary resources to contain possible impacts, help sectors that may be affected, and diversify supply chains."

Sanchez has called for dialogue to end the war on Iran, saying that "One can oppose a hateful regime and at the same time oppose an unjustified and dangerous military intervention."

Sanchez is also an outspoken critic of Israel, accusing it of carrying out genocide in its massive military operation in Gaza, an assertion Israel denies.

US forces use the Rota naval base and Moron air base in Spain. During the 2003 Iraq invasion, Spain, then under conservative prime minister Jose Maria Aznar, staunchly backed the United States.

- 'Not happy' with Britain -

Britain, a steadfast ally of the United States throughout the two World Wars and in the Iraq and Afghanistan wars, also decided not to join the assault on Iran.

"I'm not happy with the UK," Trump said, as he added of British Prime Minister Keir Starmer: "This is not Winston Churchill that we're dealing with."

Starmer said US fighter jets could use two UK air bases -- one in Gloucestershire in western England and the other at the joint UK-US Diego Garcia base in the Indian Ocean -- for a "specific and limited defensive purpose."

But Starmer said the United States was not authorized to use UK bases in Cyprus, one of which was struck by an Iranian-made drone.

"It's taken three, four days for us to work out where we can land," Trump said in apparent reference to Diego Garcia. "There would have been much more convenient landing there, as opposed to flying many extra hours."

Trump, after a series of flip-flops, has denounced Starmer for agreeing to return the Chagos Islands, home to the Diego Garcia base and whose people were expelled by Britain, to Mauritius, and instead to lease the base.

"I will say the UK has been very, very uncooperative with that stupid island that they have," Trump said.