The US State Department on Thursday ordered some US government workers to leave Venezuela and said US citizens should consider leaving the country, a day after Washington recognised an opposition politician as Venezuela's president.

"We are taking this action based on our current assessment of the security situation in Venezuela. We have no plans to close the embassy," a State Department spokesperson said in a statement.

Venezuelan President Nicolas Maduro broke off diplomatic relations with Washington and gave US embassy personnel three days to leave the country after President Donald Trump on Wednesday recognised opposition leader Juan Guaido as president.

In a security alert, the US embassy in Caracas said non-emergency US government employees had been told to leave Venezuela and American citizens should "strongly consider" departing while commercial flights were still available.