A Cuban Military boat was heavily damaged in a battle with a Cuban exile vessel neat the Bay of Matanzas off Northwest Cuba Tuesday night, a spokesman for a militant exile group said today.

The exile vessel fought with three Cuban torpedo boats and escaped without casualties, said Andres Nazario Sargen, secretary of the Second Front of Escambray and Alpha 66.

A report from a spokesman in Mexico City for the two anti-Castro groups said the Cuban vessel, which was identified there as a Chinese-made P4, apparently sank.

Nazario Sargen said the action was part of a forthcoming summer military plan against the regime of Prime Minister Fidel Castro and was staged in honor of Cuban independence hero Jose Mari, whose 114^th birthday anniversary is January 28.

"The summer military plan comprises continuous warfare action against the Fidel Castro Communist regime to raise the combatant spirit of the Cuban people and to show the exiles that there are many opportunities of joining in the fight for Cuban liberation," Nazario Sargen said in a statement.

According to Jasen's Fighting Ships, Cuban has a number of former Soviet 50-ton torpedo boats of the P4 type. They are 85 feet long.

The announcement in Mexico City was made by Patricio Sanchez.