The Trump administration has announced new sanctions on allies of Venezuela's Nicolas Maduro and financial assistance to his opponent Juan Guaido.
The moves come as an effort to deliver humanitarian aid to the economically devastated nation faltered amid strong resistance from security forces who remain loyal to the socialist leader.
US vice president Mike Pence arrived in the Colombian capital Bogota for an emergency summit of regional leaders to discuss Venezuela's crisis and immediately met with Mr Guaido.
In a speech to the group, Mr Pence urged regional partners to freeze oil assets controlled by Mr Maduro, transfer the proceeds to Mr Guaido and restrict visas for Mr Maduro's inner circle.
He said the US was imposing more sanctions on four governors aligned with Mr Maduro, including the Venezuelan politician who negotiated the release of a Utah man held in jail more than two years on what were seen as trumped up weapons charges.
He also repeated President Donald Trump's threat that "all options are on the table" - fiery language that Mr Guaido himself has adopted in what many see as a dangerous escalation of rhetoric hinting at the use of military force.
"It's time to do more," said Mr Pence.
The day is coming soon when Venezuela's long nightmare will end, when Venezuela will once more be free, when her people will see a new birth of freedom, in a nation reborn to libertad.
Mr Pence's appearance before the Lima Group - a 14-nation coalition of mostly conservative Latin American nations and Canada that has joined together to pressure Mr Maduro - comes two days after a US-backed effort to deliver humanitarian aid across the border from Colombia ended in violence over the weekend.
Forces loyal to Mr Maduro fired tear gas and buckshot on activists accompanying the supplies and set the material on fire.
Four people have been reported killed and at least 300 wounded, although only a few were taken to hospital.
For weeks, the US and regional allies had been amassing emergency food and medical kits on Venezuela's borders in anticipation of carrying out a "humanitarian avalanche" by land and sea to undermine Mr Maduro's rule.
Mr Guaido, who has been recognised as interim president by the US and 50 other governments who say Mr Maduro's re-election last year was illegitimate, called on foreign ministers to step up and do more to isolate Mr Maduro.
"Being permissive with the usurpation of power would be a threat to democracy in all of America," he said.
But he stopped short of publicly asking them to authorise the use of military force to remove Mr Maduro, as a close ally, Julio Borges, the opposition ambassador to the Lima Group, suggested on Sunday.
US officials have also avoided talk of military action.
Secretary of state Mike Pompeo did not rule out US military force but said "there are more sanctions to be had".
Any additional sanctions will increase the suffering of the Venezuelan people and may lead to more political violence, said Mark Weisbrot, co-director of the Centre for Economic and Policy Research, who advocates a negotiated end to the political crisis.
"The 'humanitarian aid' this weekend was a public relations stunt, since the aid was just a tiny fraction of the food and medicine that they are depriving Venezuelans of with the sanctions," Mr Weisbrot said.
"As the Trump administration admitted, it was an attempt to get the Venezuelan military to disobey Maduro. It was a farce, and it failed."
Mr Pence in his speech said the US would continue to search for places to pre-position aid for eventual delivery to Venezuela.
He also announced 56 million dollars in new assistance to countries in the region helping to absorb an exodus of more than three million Venezuelans who have fled hyperinflation and shortages in recent years.