Spain "will not be vassals" to another country, Deputy Prime Minister Maria Jesus Montero said on Wednesday, defying US President Donald Trump's threats to cut trade with Madrid over its stance against the US-Israeli strikes on Iran.

Trump floated imposing a trade embargo on Madrid over its refusal to allow US aircraft to use jointly operated naval and air bases in southern Spain for the offensive against Tehran. 

Spain has denounced the US and Israeli bombings of Iran as reckless and illegal, while most other European nations have withheld direct critique of the attacks.

"We are certainly not going to be anybody's vassals, we won't tolerate any threats and we'll defend our values," Montero told reporters, citing support for Spain from the European Commission.

The Commission said in a statement on Wednesday it expected the US to abide by its trade deal with the European Union and expressed "full solidarity" with member states, but stopped short of naming Spain. The EU requires that third countries treat it as a single customs bloc.

In a televised address earlier on Wednesday, Spanish Prime Minister Pedro Sanchez reiterated Spain's anti-war stance, warning that the conflict risked triggering a major global disaster.

"We're not going to be complicit in something that's bad for the world, nor contrary to our values and interests, simply to avoid reprisals from someone," said Sanchez.

One of the most outspoken critics of both Trump and Israeli Prime Minister Benjamin Netanyahu, Sanchez criticised leaders who "use the fog of war to hide their failure" at home.

"This is how humanity's great disasters start ... You cannot play Russian roulette with the destiny of millions," he said, highlighting the negative knock-on effects of the Iraq war, from a rise in jihadist terrorism to soaring energy prices, to argue that the consequences of the attack on Iran were just as nebulous.

Spain has refrained so far from involving itself in defensive operations, even as Britain, France, and Greece have sent armaments to Cyprus, which was struck by a drone on Monday, and British Prime Minister Keir Starmer authorised use of UK bases for defensive strikes on Tehran.

Israel has criticised Sanchez, accusing him of "standing with tyrants".

Embargoes

Trump on Tuesday claimed the Supreme Court's ruling in February, which declared that he could not use the International Emergency Economic Powers Act to impose tariffs because they were a tax measure, confirmed his right to apply embargoes.

Imposing a trade embargo would require making the case that Spain's refusal to permit use of its bases constituted a national emergency and posed an "unusual or extraordinary" threat to the US, said Peter Shane, a US law professor at NYU.

"It's hard to see how Spain denying us the use of air bases on its territory for us to launch an unprovoked attack on Iran poses an extraordinary threat to our national security," Shane said.

Spain sells more to the US than it buys, but certain sectors like pharmaceutical products and olive oil are more exposed through high exports.

'Cut off all trade'

"Spain has been terrible," Trump told reporters during a Tuesday meeting with German Chancellor Friedrich Merz, adding that he had told Treasury Secretary Scott Bessent to "cut off all dealings" with Spain.

"We're going to cut off all trade with Spain. We don't want anything to do with Spain," he added.

The US relocated 15 aircraft, including refuelling tankers, from the Rota and Moron military bases in southern Spain after the country's Socialist leadership said it would not allow them to be used to attack Iran.

Trump again referenced Spain's refusal to heed US calls for all NATO members to spend 5% of their GDP on defence, and added: "Spain has absolutely nothing that we need."

"All business having to do with Spain, I have the right to stop it. Embargoes - do anything I want with it - and we may do that with Spain," he said, again expressing his frustration with the Supreme Court's ruling last month that his broadest global tariffs were illegal under a national emergencies law.

Merz, speaking with reporters after the meeting, said he told Trump privately that Spain could not be excluded from a trade agreement reached between Brussels and Washington last year.

"I said that Spain is a member of the European Union and we negotiate about tariffs with the United States only together or not at all," he said. "There is no way to treat Spain particularly badly."

The US had a trade surplus with Spain for the fourth year in a row in 2025, at $4.8 billion, according to US Census Bureau data, with US exports of $26.1 billion and imports of $21.3 billion. US exports of crude oil and liquefied natural gas to Spain have grown in recent years.