Showing solidarity with opposition leaders, US Vice President Mike Pence urged Latin American allies today to further isolate Venezuela, suggesting the Trump administration would seek additional sanctions to counter the country's political crisis.

Pence, in Lima for the Summit of the Americas, announced that the US would provide nearly USD 16 million in humanitarian assistance to Venezuelans who have fled their country under the rule of President Nicolas Maduro.

"We want one message to be clear: We are with the people of Venezuela," Pence said at the US ambassador's residence, seated with a group of Venezuelan opposition leaders. The vice president called Maduro's government a "dictatorship" and said the US would continue to push a hard line against the country's leadership.

"The US and our allies, I believe, are prepared to do much more," Pence said, accusing Maduro of "refusing humanitarian aid to be delivered to Venezuela." He said the US would push "additional sanctions, additional isolation and additional diplomatic pressure beginning in our hemisphere but across the wider world." Pence is subbing for President Donald Trump after the president pulled out of his first planned visit to Latin America to manage the US response to an apparent chemical weapons attack on civilians in Syria.

The White House said Pence would sit down Saturday with Mexican President Enrique Pena Nieto, who has yet to meet with Trump in an impasse over the wall Trump has pledged to build along the US-Mexico border.

Pence's meeting with Pena Nieto will follow Trump's calls to send National Guard troops to the border. That adds further tensions as the neighbours, along with Canada, work to renegotiate the North American Free Trade Agreement.

In a series of meetings with Latin American leaders, Pence plans to promote good governance and democratic institutions and urge allies to maintain pressure on Maduro. The US has sanctioned Maduro and dozens of top officials, accusing the country of human rights abuses and sliding into a dictatorship.