CARACAS, May 19 (Reuters) - Venezuela accused the United States on Monday of violating its airspace around two small Caribbean islands over the weekend in what it said was a provocation coordinated with neighboring Colombia.

The United States said it was looking into the allegation made by the anti-U.S. government of President Hugo Chavez just two days after Venezuela accused troops from U.S. ally Colombia of crossing its border.

“This is just the latest step in a series of provocations in which they want to involve our country,” Defense Minister Gustavo Rangel said at a news conference.

The U.S. ambassador in Caracas was being summoned to explain the incident, Venezuela’s foreign minister said.

“We respect Venezuela’s sovereignty and I am sure we will look into the allegations and provide them with an answer,” U.S. State Department spokesman Sean McCormack said in Washington.

A U.S. Navy warplane on Saturday entered the airspace around La Orchila and another island about 80 miles (120 km) from the South American country’s mainland, Rangel said.

La Orchila has a military base and a presidential residence and is well-known because Chavez was held prisoner there during a brief coup against him in 2002. Venezuela generally bans all but its military from flying over the island.

Venezuelan authorities contacted the U.S. plane and the pilot said he would head back to another Caribbean island, Curacao, a former Dutch colony which the United States uses for training, Rangel said.

Chavez frequently says the United States and Colombia plot to invade Venezuela, one of the largest oil exporters to the United States. The two countries dismiss the general accusation and Colombia specifically denied Saturday’s incursion charge.

The new accusations came against a backdrop of tensions between Venezuela and Colombia and the United States, which both said last week an Interpol investigation showed Chavez’s links to Marxist Colombian rebels, despite his denials.

Rangel said such airspace violations probably happened in the past but that Venezuela now has equipment to detect flights in the area.

“This sort of event cannot be allowed, just left to one side,” Rangel said. “As a serious state we have to really and truly assume a defensive stance.”