The U.S. State Department says American's shouldn't travel to Venezuela, warning of unrest and the threat of being arbitrarily arrested.
Tuesday's announcement raises the travel advisory to its highest level.
Venezuela is gripped by escalating political instability as U.S.-backed opposition leader Juan Guaido presses to oust socialist President Nicolas Maduro.
Officials have cleared the U.S. embassy in Caracas of everybody but essential staff.
The travel advisory warns of the threat of kidnapping, robberies and mass demonstrations occurring with little notice.
Opposition leaders have called for anti-government demonstrations this week.