The United States, Canada and major South American nations recognised the head of Venezuela's opposition-controlled legislature, Juan Guaido, as the country's interim leader on Wednesday, leaving President Nicolas Maduro increasingly isolated.

Major regional players Brazil, Colombia, Chile, Peru and Argentina all gave their backing to Guaido's self-proclamation as Venezuela's acting president, which he made in front of crowd of tens of thousands of supporters in Caracas.

Mexico, however, stood apart, saying it recognises "the authorities elected in accordance with the Venezuelan constitution," seen as a lukewarm nod to Maduro. Separately, Mexico and Uruguay urged all internal and external parties involved in the crisis to defuse tensions and prevent an escalation of violence. Cuba, meanwhile, expressed its "firm support" for Maduro after what it called a "coup attempt", while Bolivia's leftist President Evo Morales affirmed his long-standing alliance with the Venezuelan president.

But the avalanche of support for Guaido dramatically raised the stakes in Venezuela, an oil-rich nation has become deeply impoverished under Maduro.

Maduro has clung to power through the support of the Venezuelan military, and he is an ally of Russia, which last month sent two nuclear-capable bombers to the country to participate in a military drill.

The US said on Wednesday that it stood ready to use "all options" if Maduro tried to quash the opposition, in what was an implied threat of military force.

190123205835912

President Donald Trump said Guaido's National Assembly was "the only legitimate branch of government duly elected by the Venezuelan people".

Maduro responded by saying he was cutting off diplomatic ties with the US, as his riot police clashed with opposition supporters in Caracas.

"Get Out! Leave Venezuela. Here we have dignity, damn it," Maduro said, giving US diplomats 72 hours to depart.

But Guaido tweeted in response a statement that, under him, Venezuela wants countries "to maintain their diplomatic presence in our country".

Tweeting from the Swiss ski resort of Davos, where he and other leaders were attending the World Economic Forum, far-right Brazilian President Jair Bolsonaro said, "Brazil recognises Mr Juan Guaido as Venezuela's interim president."

He added that "Brazil will support politically and economically the process of transition so that democracy and social peace return to Venezuela."

190117184349473

Bolsonaro, who has set about forging close ties with Trump's administration since taking power at the beginning of January, has repeatedly vowed to challenge Maduro in any way he can.

Colombian President Ivan Duque, another US ally also at Davos, told reporters his country was behind Guaido and will "accompany this process of transition to democracy so that the Venezuelan people free themselves of their dictatorship."

Canadian Foreign Minister Chrystia Freeland expressed her country's "full support" for Guaido, adding: "It's an important day for Venezuela and I'm grateful for the solidarity of the Lima Group in speaking out on this."

Lima group mostly supports Guaido

Eleven members of the 14-nation Lima Group - Argentina, Brazil, Canada, Chile, Colombia, Costa Rica, Guatemala, Honduras, Panama, Paraguay and Peru - later issued a joint statement endorsing Guaido as interim president.

The three holdouts included Mexico, which has maintained a principle of non-intervention under leftist President Andres Manuel Lopez Obrador, as well as Guyana and Santa Lucia.

190123130712024

Lopez Obrador's spokesman said on Twitter that while Mexico "for the moment" was not changing its relations with Caracas, it was "analysing the situation in Venezuela."

The US is not a member but supports the group, which has taken an increasingly strident stance against Maduro.

The European Union did not join the countries lining up behind Guaido, but EU Council President Donald Tusk tweeted that "I hope that all of Europe will unite in support of democratic forces in Venezuela."

Tusk added, "Unlike Maduro, the parliamentary assembly, including Juan Guaido have a democratic mandate from Venezuelan citizens."