About 40 demonstrators gathered yesterday near the Philippine Embassy in Northwest Washington to protest a Philippine court's acquittal of armed forces chief of staff Gen. Fabian C. Ver and 25 other persons in the 1983 assassination of opposition leader Benigno Aquino.

Carrying signs that called for the resignation of Philippine President Ferdinand Marcos and a halt to U.S. military aid to that country, the group demonstrated for about a half-hour before sending a delegation to the embassy to deliver a letter of protest to officials there.

There were no arrests.

Earlier yesterday, a three-judge tribunal, ruling after a seven-month trial, dismissed the contention of a civilian commission that Aquino was shot by one of the government security agents who were escorting him from a plane in Manila as he returned from three years of exile in the United States.

Ver and other high-ranking military officials were accused of conspiring in the slaying. After the court's ruling, Ver was reinstated as the head of the armed forces.

One of the leaders of yesterday's demonstration here, a nephew of the slain opposition leader who also is named Benigno Aquino, called the court's verdict "a big insult to the U.S. government . . . . The U.S. government was the one who led us to democracy, and now they are letting these things happen."

The protesters, who gathered shortly after noon, were blocked from advancing within 500 feet of the embassy at 1617 Massachusetts Ave. NW. Four of the demonstration's organizers were allowed to deliver to an embassy official a letter that was signed by several exiled opposition leaders and Philippine human rights workers here.

The unidentified embassy official received the letter without comment from behind a chain-link gate at a side entrance.