WASHINGTON, Jan. 10 (Xinhua) -- The U.S. Department of State's Bureau of Consular Affairs on Saturday warned that as international flights have resumed, U.S. citizens in Venezuela "should leave the country immediately."

The bureau said in a post on X that the security situation in Venezuela "remains fluid" and there are "reports of groups of armed militias, known as colectivos, setting up roadblocks and searching vehicles for evidence of U.S. citizenship or support for the United States."

U.S. citizens are advised to "remain vigilant and exercise caution" when traveling by road and to monitor airlines' communications and websites for updated information.

"Venezuela has the highest Travel Advisory level -- Level 4: Do Not Travel -- due to severe risks to Americans, including wrongful detention, torture in detention, terrorism, kidnapping, arbitrary enforcement of local laws, crime, civil unrest, and poor health infrastructure," the bureau said.

The United States launched a large-scale military operation against Venezuela in the early hours of Jan. 3, taking by force Venezuelan President Nicolas Maduro and his wife. The strikes have drawn worldwide condemnation and concern.