Nicaragua yesterday disputed U.S. statements about a military incident Monday and charged that it was "a provocative action" by the United States aimed at creating "unnecessary tensions."

The incident was announced Monday night by the State Department, which said a Nicaraguan patrol boat had fired on an unarmed helicopter from the U.S. frigate Trippe. The State Department said the ship and helicopter were in international waters more than 12 miles from the Nicaraguan coast.

A press release from the Nicaraguan Embassy yesterday, accompanied by a map, said the U.S. ship was "approximately three miles" from the coast in the Gulf of Fonseca when encountered by a Nicaraguan patrol boat. As the Nicaraguan boat approached, the U.S. vessel dispatched a helicopter "which headed toward the patrol boat in a bellicose manner."

The statement said the patrol boat fired "warning shots," and the helicopter returned to the warship.

Informed of the Nicaraguan charges, a Defense Department spokesman repeated that "at no time was the ship or the helicopter closer than 12 miles" from shore. A Defense official who declined to be named put the location of the incident about 13 miles off the Pacific coast of Nicaragua, not in the Gulf of Fonseca.

The spokesman declined to say what the U.S. frigate was doing in the area, which has been reported to be under U.S. surveillance because of suspected supply and infiltration from Nicaragua to rebel forces in El Salvador.

The U.S. official said the helicopter had been launched when the warship detected the Nicaraguan craft, and was about one mile from the patrol boat when it was fired upon.