JAKARTA, Indonesia - Pro-Indonesia militias may be planning guerrilla raids on the Australian-led international peacekeepers in devastated East Timor, American officials said yesterday.

Defense Secretary William Cohen said he would raise the matter today in meetings with Indonesian military and government officials and stress that there must be no Indonesian army involvement - or even tacit support - for violence against the peacekeepers.

Speaking yesterday at the Royal Australian Air Force headquarters in Darwin, where he met with officials from Australia and New Zealand and greeted several dozen troops, Cohen said there was reason for concern about cross-border militia attacks.

"That's one of the apprehensions we have,'' Cohen said.

He is scheduled to meet with Gen. Wiranto, the Indonesian military chief, as well as President B.J. Habibie and Megawati Sukarnoputri, the daughter of Indonesia's founder and the expected next elected president. Cohen also will meet with Indonesian finance officials and representatives of area human rights organizations.

A senior U.S. defense official traveling with Cohen told reporters there are indications that pro-Indonesia militias - numbering between 2,000 and 4,000 - may be preparing to launch guerrilla raids on the Australian-led peacekeeping troops in East Timor. The official, who spoke on condition he not be identified, offered no other details.

Asked about the potential for militia attacks, Marine Corps Brig. Gen. John G. Castellaw, commander of the U.S. forces supporting the East Timor operation, told reporters he would "not speculate on that.'' He added that Australian officials had assured him they are well prepared to defend themselves and the rest of the peacekeeping operation.

Upon his arrival last night in Jakarta, Cohen said that with the peacekeepers now in East Timor and "with some stability returning there,'' he sees a chance that order can be restored and relations with Indonesia put back on track.

The Clinton administration cut off military relations with Indonesia on Sept. 8 in response to the Indonesian army's collusion with militia groups in attacking pro-independence civilians in East Timor following a referendum there that overwhelmingly voted for independence from Indonesia. East Timor is a former Portuguese colony.

During his stop in Darwin, Cohen announced that the Pentagon is dispatching the helicopter carrier USS Belleau Wood to the waters off East Timor and increasing its satellite communications support for the international peacekeepers there. Cohen reiterated that no American combat troops would be sent.

At a news conference with Australian Defense Minister John Moore, Cohen said four heavy-lift Marine Corps helicopters will operate from the deck of the Belleau Wood to ferry equipment around East Timor for the peacekeepers. They also may fly to East Timor from Darwin on the north Australian coast, a few hundred miles from East Timor.

"We are very pleased indeed for that expansion'' of the U.S. contribution, Moore said. Australia ''could not want for more'' from the Americans, who are offering capabilities no other country could provide, he said.

The helicopter carrier, with an 820-foot flight deck and crew of about 900 Marines, is loading in Okinawa and will depart today, said Cohen spokesman Kenneth Bacon. The ship is expected to be near East Timor on Oct. 6 and will remain in the area at least until the end of October. Its home port is Sasebo, Japan.