Brazil’s Gol, Colombia’s Avianca, and TAP Air Portugal have cancelled their flights departing from Caracas on Saturday, according to Flightradar24 and Maiquetia International Airport’s official website.

Aeronautica Civil de Colombia said in a statement there were “potential risks” of flying in the Maiquetia area “due to the deterioration of security conditions and increased military activity in the region”.

Spain’s Iberia also said they were cancelling their flights to Caracas from Monday until further notice.

The Spanish company’s flight scheduled for Saturday to Madrid from Venezuela’s capital departed.

“The company will assess the situation to decide when to resume flights to that country,” an Iberia spokesman told Reuters.

Copa Airlines and Wingo kept their flights departing from Maiquetia on Saturday.

The US FAA notice cited the “worsening security situation and heightened military activity in or around Venezuela” and said threats could pose risks for aircraft at all altitudes.

There has been a massive American military buildup in the region in recent months, including the US Navy’s largest aircraft carrier, at least eight other warships, and F-35 aircraft.

“Latam Airlines flight to Bogota scheduled for Sunday has also been cancelled,” Flightradar24 says.