Philippine marines who were searching for long-held hostages battled al-Qaida-linked militants in a fierce clash that killed four marines and at least two insurgents in the country's south, officials said.

The fighting erupted in the mountainous hinterlands of Patikul town in Sulu province, where the Abu Sayyaf movement has survived in jungle encampments despite years of U.S.-backed Philippine military offensives. Twenty-two marines were wounded in the daylong clash Sunday that involved up to 200 Abu Sayyaf fighters and their allies, officials said.

Regional military commander Maj. Gen. Rey Ardo ordered air force planes and navy ships to back up government forces, ensure the recovery of the slain marines and transport the wounded to a hospital. However, bad weather delayed the rapid deployment of assault helicopters and by the time they flew over, the militants had dispersed, the marines said.

Regional military spokesman Lt. Col. Randolph Cabangbang said the marines had been deployed in Patikul to check the reported sighting of hostages held by the Abu Sayyaf, which has been blamed for separate kidnappings of two Europeans, a Japanese, a Jordanian and two Filipinos. They stumbled upon the militants under Abu Sayyaf commander Radulan Sahiron and gunmen loyal to Tahir Sali, a commander of the larger rebel group Moro National Liberation Front.

Sahiron and Sali, who maintain encampments in Patikul's jungles, have long been suspected of collaborating to carry out ransom kidnappings to raise funds.

The Europeans — Ewold Horn of the Netherlands and Lorenzo Vinciguerra of Switzerland — were seized by gunmen in February while bird watching in the southernmost island province of Tawi Tawi. They were later moved to nearby Jolo Island in Sulu province, where they have been seen by villagers in the custody of Abu Sayyaf gunmen, according to police.

Police initially believed the two were seized by ordinary kidnapping gangs.

Aside from the Europeans, the militants are believed to be holding a Japanese treasure hunter, along with a Jordanian TV journalist and two Filipino crewmen who reportedly traveled to Abu Sayyaf camps in Sulu to interview the militants in June but have failed to return.

While Abu Sayyaf abductions still occur, they are far fewer today than the massive kidnappings that terrorized Sulu and outlying provinces in early 2000 when the brutal group still had many commanders and strong ties with terrorist organizations including the Indonesian-based Jemaah Islamiyah.

The militant Islamist movement has also received support in the past from al-Qaida.