ZAMBOANGA CITY, Philippines (AP) _ An armed gang shot out the tires of a Roman Catholic bishop's minibus Friday and kidnapped the party of 11 people, forcing them into the southern Philippine bush.

Spokesmen for the military said they believed the abductors were Moslem secessionist rebels. Both the Moslem bands and Communist guerrillas roam the area of Mindanao island around the highway on which the Most Rev. Federico Escaler was traveling to Zamboanga with his party of three nuns and seven other companions.

The Rev. Jose Bacatan of the Jesuit-run Ateneo de Zamboanga college said word of the kidnapping was relayed to Escaler's fellow Jesuits by two women in the bishop's party who were freed after about three hours. He said the abductors apparently let them go because they could not keep up with the march through the rough hill country.

A military officer, who spoke on condition he not be identified, said troops were sent in to look for the 63-year-old bishop, who is an outspoken critic of President Ferdinand Marcos' government. He said two helicopters were dispatched in hopes they could spot the marchers and track their movements though the hinterlands of Zamboanga del Sur province, 490 miles south of Manila.

The officer said the kidnappers were believed to be either members of the Moro National Liberation Front, which has been fighting for Moslem rule in the southern Philippines for more than a decade, or a splinter band of that group.

The bishop and his party were bound for Zamboanga from his diocese in Ipil, 70 miles away, when the minibus was waylaid at about 9 a.m.

Bacatan said the two released women, one a 63-year-old retired teacher, reported that three armed men in fatigue uniforms shot out the rear tires of the bishop's vehicle when it ignored a signal to stop. About 15 more men appeared on the road and marched the occupants off into the hills, the women said.

He said the two women, Tessa Molina and Lilia Ignacio, watched the hostages and their captors walk deeper into the bush before returning to the highway.

Bacatan said the women told officials in the nearest town about the kidnapping and boarded a bus to Zamboanga.

Kidnappings are fairly common in the southern Philippines, but it was the first time a bishop in this predominantly Catholic nation has been abducted.

The hostages, besides Bishop Escaler, are the three nuns, a school principal, two students, the bishop's secretary and his driver, Bacatan said.

The abduction occurred about 150 miles from the island of Jolo, where Moslem separatists have been holding John Robinow of New York City and Helmuth Herbst of Munich, West Germany, since Nov. 19.

The rebels, who dropped demands for a $25,000 ransom after the U.S. and West German embassies refused to pay, made arrangements to free the two men late last month, but changed their minds. They said the Pakistani ambassador, who was to receive the hostages, did not show the proper credentials.