Delegates from some 60 countries will meet Tuesday in Lima to discuss the political crisis in Venezuela, as Washington steps up pressure for President Nicolas Maduro to step down.

The conference comes a day after President Donald Trump ordered a freeze on all Venezuelan government assets in the United States and barred transactions with its authorities "in light of the continued usurpation of power" by the socialist leader.

The meeting has been convened by the Lima Group, which includes a dozen Latin American countries and Canada and is helping to mediate in the crisis.

Mr Trump’s National Security Advisor John Bolton and Commerce Secretary Wilbur Ross are in the US delegation, which is expected to announce further punitive measures against Mr Maduro at the meeting in the Peruvian capital.

The "sweeping steps" will have "a lot of potential consequences", Mr Bolton said, stressing that Mr Trump is committed to a transition of power in Venezuela.