The US military action in Venezuela breaches international law and the UK should make clear it is “unacceptable”, the chair of the Commons Foreign Affairs Committee has said.

Dame Emily Thornberry is the most senior Labour MP so far to criticise Donald Trump’s strikes on the country over the weekend, which saw President Nicolas Maduro and his wife seized.

The UK government has so far refused to say whether the move was illegal, insisting it is for the Americans to lay out the legal basis for the action.

But the US president’s actions have been criticised by some Labour MPs, as well as the leaders of the Lib Dems, Greens and the SNP.

Dame Emily told BBC Radio 4’s Westminster Hour the strikes were “not a legal action” and she “cannot think of anything that could be a proper justification”.

She said the UK and its allies should collectively say “we cannot have breaches of international law like this. We cannot have the law of the jungle.”

She added: “We condemn Putin for doing it. We need to make clear that Donald Trump shouldn’t be doing it either.

“People just can’t do whatever they want. I mean, we really can’t have a kind of international anarchy.”

Warning the US action risked emboldening Russia and China, she said: “This growing idea that Trump thinks, and so does [Russian President] Putin and so does [Chinese President] Xi, that they should all have their spheres of influence and that other countries should not get involved and they should be able to essentially do what they think is the right thing to do, what they want to do in the interests of their country, in the countries in the surrounding area…

“President Putin will presumably say, well, Ukraine is in my sphere of influence – what are you complaining about? And Xi may well say that about Taiwan. It sets a terrible precedent and [is] really worrying.”

A handful of Labour MPs – mostly on the left of the party – have publicly condemned the US action for breaking international law so far.

However, more could criticise the UK’s response in the House of Commons later, when the foreign secretary gives a statement on the developments in Venezuela.

Prime Minister Sir Keir Starmer has made his relationship with Donald Trump a key element of his foreign policy and has not condemned the US strikes.

In an interview with the BBC on Monday he again sidestepped questions about whether the military action was illegal.

He insisted the UK would “always defend the international rule of law” but the US would “have to justify the action it has taken”.

“There was an illegitimate president who has now been removed, and I don’t think anybody is really shedding any tears about that,” he said, calling for “a peaceful transition to democracy” as soon as possible.

The UN Security Council, of which the UK is a permanent member, is meeting to discuss the US operation.

Earlier, minister Mike Tapp refused to say whether the UK would abstain in any vote on the legality of the action, saying it had not yet seen the “legal basis” for the US strikes so a decision could not be made.

The government is facing calls from some opposition parties to condemn the US military action, with the Liberal Democrats, the Green Party and the Scottish National Party all criticising the strikes.

Lib Dem leader Sir Ed Davey said Maduro was “a brutal and illegitimate dictator” but “unlawful attacks like this make us all less safe”.

Green Party leader Zack Polanski also branded the strikes a breach of international law, while the SNP’s John Swinney said it was “absolutely essential that all nations act within the international rules based system”.

However, the Conservative Party said it was important to understand the full facts about the operation before rushing to judgement.

Shadow minister Alex Burghart said that in an era of strongmen it was “totally understandable” the US would act against Venezuela.

“Whatever international lawyers say about whether this was legal or not, Maduro had not been following international law for some considerable time,” he added.

Reform UK leader Nigel Farage said the US action was “unorthodox and contrary to international law” but if it makes China and Russia “think twice, it may be a good thing”.

Venezuela’s left-wing president and his wife Cilia Flores were flown out of Caracas in a military operation in conjunction with US law enforcement.

They have since been charged with weapon and drug offences in New York, accused of enriching themselves from a violent crime ring smuggling cocaine to the US, and are expected to appear in court later.

Maduro has long rejected the allegations as a pretext to force him from power.

Trump has vowed to “run the country” until there is a “proper” transition of power, with Venezuela’s Vice-President Delcy Rodríguez due to be sworn in as interim president later.