The U.S. is warning pilots to use caution when flying to or over Venezuela because of civil unrest there.
The Federal Aviation Administration said there is no evidence to suggest that Venezuela's military would target civilian planes, but it said mistakes are possible.
And warned that some of the military's shoulder-launched anti-aircraft missiles could fall into the hands of groups "who may have different intent and a lower level of training."
The FAA issued a notice Friday warning pilots to use caution when flying lower than 26,000 feet over the country.
Several airlines halted flights to Venezuela as chaos and political strife grew, but a few still fly there.
"We continue to serve two airports in Venezuela, and our team is closely monitoring the situation in coordination with the FAA," American Airlines spokesman Ross Feinstein said Monday. American flies daily from Miami to Caracas and Maracaibo.
The FAA's notice stopped short of banning U.S. airlines from flying to Venezuela. The FAA generally bans flights over North Korea and six other nations.
In a similar warning about North Korean missile tests, the FAA advises pilots and airlines to be cautious about flying over Japan and a large swath of the Pacific Ocean that is heavily used by flights between the U.S. and Asia — but does not ban such flights.
The FAA warning raises comparisons to the situation in Ukraine in 2014, when a Malaysia Airlines jet flying from Amsterdam to Kuala Lumpur was shot down by a missile while flying over eastern Ukraine, where pro-Russian rebels were fighting the Ukrainian military. All 298 people on the plane died.
The Netherlands and Australia blame Russia for arming the rebels suspected of firing the missile. The Dutch safety board said this month that airlines still need better information to make judgments about the risk of flying over war zones.