WASHINGTON -- Two US F-18 fighter jets entered Venezuelan airspace on Tuesday, circling for about 40 minutes, according to a report from the Miami Herald, a newspaper based in the US state of Florida.

FlightRadar24 showed them flying over the northern tip of Lake Maracaibo, above the waters of the Gulf of Venezuela, right between the cities of La Guajira, in Zulia, and Coro, the capital of Falcon state, said the report. Zulia and Falcon are among the key regions for Venezuela's energy sector.

Thousands of Venezuelans tracked the aircraft online through specialized tracking websites, watching as the jets traced a bow-tie-shaped pattern over the gulf, said the report, noting the jets flew at an altitude of roughly 25,000 feet (about 7,620 meters).

Lake Maracaibo, covering 5,000 square miles (about 12,950 square km), is one of the largest bodies of water in the Americas and the heart of reserves containing some 150 billion barrels of crude oil, the report noted.

The flyover is less than 100 miles (about 161 km) northeast of Maracaibo, Venezuela's second-largest city and home to the Rafael Urdaneta Air Base, one of the main military air bases in western Venezuela.

In an interview with Politico on Monday, US President Donald Trump repeatedly declined to rule out sending US troops into oil-rich Venezuela as part of an effort to topple Venezuelan President Nicolas Maduro.

"I don't want to rule in or out. I don't talk about it," Trump said of deploying ground troops, "I don't want to talk to you about military strategy."

Trump has recently reiterated that the US military is to start strikes on land targeting drug traffickers in the Caribbean "very soon," escalating tension between the United States and Venezuela.

The Pentagon has carried out at least 22 known strikes on alleged drug vessels in the Caribbean and eastern Pacific Ocean since September, killing at least 87 people aboard.

Washington has deployed around a dozen warships, including the USS Gerald R. Ford, a major aircraft carrier, and about 15,000 troops to the Caribbean Sea, which shares a significant amount of coastline with Venezuela. The region has not seen such a massive US military presence for at least three decades.

Critics, including multiple lawmakers at the US Capitol, have questioned whether counternarcotics are indeed the only US motive and the legality of the US military strikes in the Caribbean.

Maduro has repeatedly condemned Washington's actions as attempts to overthrow his government and expand the US military influence in Latin America.