The United States is suspending $2.7 million in military assistance to Nicaragua (search) because President Enrique Bolanos (search) has not followed through on a promise to destroy surface-to-air-missiles, a State Department official said Monday.

The administration is concerned that the missiles, left over from the Central American wars of the 1980's, could fall into the hands of terrorists and be used to attack commercial flights.

The State Department official, asking not to be identified, said the missiles are believed to be in the custody of the Nicaraguan military.

The official said Bolanos assured President Bush that the missiles, believed to number about 1,000, would be destroyed.

Rose Likins, a senior official from the State Department political-military affairs bureau, visited Managua a month ago to reaffirm American concerns.

At the time, Likins said Nicaragua was the only Central American nation with such missiles, which she described as the "preferred weapons" of terrorists.

At issue are Soviet-made SA-7's (search), which were made available by Moscow to Nicaragua's Sandinista government in its war with the U.S.-backed Contra rebels (search) two decades ago.

The heat-seeking missiles can hit low-flying aircraft within a range of three miles.

The Sandinistas (search) were voted out of power in 1990, and have been succeeded by a succession of governments friendly to the United States since then.

But former Sandinista President Daniel Ortega (search) is captaining political forces in the country opposed to destruction of the missiles. He has denounced the U.S. demands as an intrusion on Nicaraguan sovereignty.

The Sandinistas joined with another opposition group in approving legislation to prevent Bolanos from destroying the weapons.