Updated

MANILA, Philippines (AP) — Al Qaeda-linked militants beheaded three loggers in the Philippines in apparent retaliation for government offensives in the country's south, security officials said Sunday.

The killings were carried out as the country celebrated its 112th Independence Day, the latest in a series of terror acts by the Abu Sayyaf insurgency to mark the holiday.

About 30 Abu Sayyaf gunmen ran into the three Christian men hauling timber in a rain forest near Maluso town on Basilan island Saturday. Relatives found their remains hours later, Basilan provincial police chief Antonio Mendoza said.

The latest killings apparently were a retaliation for the ongoing military and police operations, which have killed a number of militants, Mendoza said.

"When they are hurt by our offensives, they resort to these atrocities," Mendoza told The Associated Press, adding that all of Basilan's 675-strong police force, with an additional 100 police commandos, were involved in the manhunt and assaults against the militants. Hundreds of soldiers also are taking part.

This was the second time that Abu Sayyaf was blamed for beheading a hostage on Independence Day after they killed American Guillermo Sobero in 2001 as their holiday "gift" to President Gloria Macapagal Arroyo. Another American was killed in a military rescue a year later.

Despite years of U.S.-backed offensives, nearly 400 Abu Sayyaf fighters have survived in Basilan and on nearby Jolo island and the Zamboanga peninsula. They remain a major security concern as part of a decades-long Muslim insurgency.

The Abu Sayyaf, founded in Basilan in 1991, is believed by U.S. and Philippine security officials to have received funds and training from Osama bin Laden's network.

A ruthless commander, Puruji Indama, led the group behind Saturday's beheadings, Mendoza said. A search for Indama and his men was under way in the jungles near Maluso, which is near Sumisip township — scene of most military and police operations against the Abu Sayyaf in recent weeks, he said.

Indama's group has also been blamed for the killings of three hostages and two villagers near Sumisip on June 4 in attacks that followed the death of three Abu Sayyaf fighters in a clash with army Scout Rangers the same day.

Government troops have mounted an offensive in and around Sumisip in Basilan, a predominantly Muslim island about 550 miles (880 kilometers) south of Manila, amid intelligence reports that a number of militants allied with the Southeast Asian militant network Jemaah Islamiyah have taken refuge in Abu Sayyaf encampments.

Among the militants is Malaysian Zulkifli bin Hir, also known as Marwan, a U.S.-trained Malaysian engineer accused by Philippine authorities of involvement in a number of deadly bombings in the Philippines.

The United States has offered a $5 million reward for Marwan's capture.