World Notes THE PHILIPPINES

For the past 18 years, Communist guerrillas of the New People's Army have made Philippine soldiers and policemen their main targets. Last week they turned their guns on Manila's main foreign backer: the U.S. In one well-coordinated 15-minute burst of violence, pistol-wielding assassins killed two active-duty U.S. service members, a retired U.S. sergeant and a Filipino businessman. The attacks occurred within three miles of Clark Air Base, the largest overseas U.S. Air Force facility. All bore the signature of the N.P.A.'s sparrow-unit death squads, so called for their small size and great mobility. Persons claiming to represent the N.P.A. took responsibility for the murders, which came just one week after President Corazon Aquino vowed to crack down on the Communist insurgents.

In Manila alone, some 50 killings have been attributed to the sparrows this year. The N.P.A. had threatened to target American personnel after the U.S. announcement of increased military aid to Manila following the August coup attempt. Indeed, the guerrillas boasted that they would kill one American for each of the ten armored personnel carriers that the Reagan Administration delivered to the Aquino government last week. U.S. military officials ordered service members and their families at both Clark and the Subic Bay naval base to restrict travel outside the camps to essential trips and to avoid using side roads.