The United States pressed all nations Saturday to "stand with the forces of freedom" in Venezuela, encouraged by a tougher European line as Russia stood in the minority in backing embattled leader Nicolas Maduro.

US Secretary of State Mike Pompeo made a forceful case at a special session of the United Nations Security Council, where he described Maduro as part of an "illegitimate mafia state" responsible for Venezuela's economic collapse.

Four major European countries - Britain, Germany, Britain, France and Spain - said on Saturday they are ready to recognise Juan Guaido as Venezuela's interim president if elections are not called within eight days.

Jeremy Hunt, the British foreign secretary, said: "After banning opposition candidates, ballot box stuffing and counting irregularities in a deeply flawed election it is clear Nicolas Maduro is not the legitimate leader of Venezuela," Mr Hunt tweeted.