Seeking to demonstrate their commitment to peace after 15 years of conflict, as many as 60 rebels of the outlawed Kurdish Workers' Party in northern Iraq are heading toward the Turkish border to turn themselves in to Turkish authorities, sources close to the guerrillas said today.

Senior rebel commanders are among the group--whose members wore the rebel uniform of baggy trousers with colorful cotton cummerbunds and carried assault rifles. The commanders are carrying three letters addressed to senior Turkish leaders calling for peace, according to the sources, who said they had witnessed the journey.

The move, which followed a call by the rebel group's imprisoned leader, Abdullah Ocalan, for a "show of goodwill," is the most conciliatory gesture by the guerrillas since they launched their armed campaign for Kurdish independence in southeastern Turkey 15 years ago. More than 30,000 people have been killed in the conflict.

This move follows a series of overtures to the Turkish authorities by Ocalan since his capture in February and his conviction on terrorism charges in June. Last month, leaders of the 8,000-member guerrilla movement announced that they would abandon their insurgency and pursue greater Kurdish rights nonviolently.

To guarantee their safe passage to the Turkish border, the group of rebels traveling to Turkey is negotiating with U.N. officials based in the Kurdish enclave in northern Iraq. "They want to ensure that U.N. officials will be the ones to hand them over to the Turks," one of the sources said. U.N. officials could not be reached for comment.

Analysts said the rebel move is calculated to pressure the Turkish government to grant the country's 12 million Kurds greater political and cultural rights.

It also comes just before Prime Minister Bulent Ecevit's visit to Washington, where he is scheduled to meet President Clinton on Tuesday. U.S. officials involved in arranging the visit say the Kurdish issue likely will come up during the talks, which are to focus primarily on possible U.S. aid to help rebuild areas flattened by the Aug. 17 earthquake.

Ecevit has said he would welcome a guerrilla surrender but has made clear they would have to comply with the conditions of a recently approved amnesty bill, which says that only rebels who have not been involved in violence will be pardoned.

Since a Turkish court sentenced him to hang, Ocalan, 51, has called on his followers to end their uprising and withdraw from their bases in the rugged mountains of Turkey's largely Kurdish southeast. Ocalan has said that Kurdish independence is no longer "a realistic goal," and that easing bans on broadcasting and education in the Kurdish language would now largely satisfy the Kurds' demands for greater recognition.

An appeals court is reviewing Ocalan's case and is widely expected to uphold the death sentence next month. But the Turkish parliament and president must approve his execution before it can be carried out.

U.S. officials said there are "unmistakable signs" that the Turkish government and, more importantly, the powerful military are softening their stand on the Kurds. They point to comments by Gen. Huseyin Kivrikoglu, the armed forces commander in chief, who said this month that the decision whether to execute Ocalan was a political one, and that Kurdish-language television broadcasts and literature already are tolerated.

His remarks were widely interpreted as a signal that the military will not press for Ocalan's execution and will no longer oppose moves to grant the Kurds cultural rights.