The UK, France, Germany, Spain and other European countries have officially recognised opposition leader Juan Guaidó as interim president of Venezuela.
It comes after President Nicolás Maduro defiantly rejected the EU’s Sunday deadline to call snap elections.
Mr Guaidó declared himself interim leader last month and won US backing.
Russia – a backer of Mr Maduro – accused EU countries of meddling in Venezuela’s affairs.
As pressure mounted on Mr Maduro to step down, he said he could not rule out the possibility of civil war.
In a TV interview, he warned that US President Donald Trump would leave the White House “stained with blood” if he intervened militarily in the crisis, which arose after Mr Maduro’s disputed re-election last year.
Mr Guaidó said on Sunday he would build an international coalition to deliver humanitarian aid to Venezuelans.
As head of Venezuela’s National Assembly, Mr Guaidó says the constitution allows him to assume power temporarily when the president is deemed illegitimate.
Sunday saw the expiry of an ultimatum set by European countries including France, the UK, Germany and Spain for Mr Maduro to call early presidential elections. They said that they would recognise Mr Guaidó as interim president if no such pledge was forthcoming.
