Washington has amassed a huge flotilla of warships in the Caribbean as part of what it bills as counter-narcotics efforts, and has since September carried out strikes targeting alleged drug-smuggling vessels that have left nearly 90 people dead.

Regional tensions have flared as a result of the strikes and the military buildup, with Venezuela's leftist leader Nicolas Maduro accusing Washington of using drug trafficking as a pretext for regime change in Caracas.

According to data from tracking website Flightradar24 analyzed by AFP, two US Navy F/A-18 jets circled the Gulf of Venezuela for more than 40 minutes on Tuesday, approaching within a little over 20 miles (35 kilometers) of the coast.

Another warplane was also in the air further north at the start of the mission.

The same day, a long-range surveillance drone made repeated passes for several hours along a 500-mile stretch of the Caribbean Sea -- the first time a drone of that type transmitted a signal in the area in at least a month.

Another high-altitude drone flight took place in the same area on Friday morning.

Additionally, there have also been five flights of B-1 and B-52 bombers and two flights of F/A-18s within 25 miles of the Venezuelan coast between late October and late November.

Other aircraft not included in the data have also been in the skies over the Caribbean -- for instance, photos released by the US military have showed bombers being accompanied by F-35 stealth jets that did not appear on Flightradar24.

Washington has accused Maduro of leading the alleged "Cartel of the Suns," which it declared a "narco-terrorist" organization last month, and has offered a $50 million reward for information leading to his capture.

President Donald Trump told Politico on Monday that Maduro's "days are numbered" and declined to rule out a US ground invasion of Venezuela.