18 soldiers wounded in ongoing clash with Abu Sayyaf extremists in southern Philippines

The military launched a strike on Abu Sayyaf extremists in the southern Philippines early Friday and ongoing clashes have left at least 18 soldiers wounded, officials said.

Lt. Col. Ramon Zagala said 200 troops were deployed before dawn to flush out some 20 militants led by Puruji Indama, a commander of the militant Muslim group, from a village in Basilan island's Unkaya Pukan township.

The extremists later occupied school buildings in nearby Tipo-tipo township, said Brig. Gen. Carlito Galvez, an army brigade commander in the area. The school is empty because students are on summer break.

Galvez said the military operation was intended to seize Indama and his group, who have threatened and tried to extort money from a road construction project in the province.

Indama has been wanted by Philippine authorities for his alleged involvement in deadly bombings and kidnappings, including of a former Australian soldier freed last year after 15 months of jungle captivity and payment of ransom. He also has been blamed for the 2007 beheadings of 10 marines in Basilan, a widely condemned atrocity.

Zagala said he had no immediate information on Abu Sayyaf casualties and more details may be available when the smoke of battle clears.

"We're continuing the pressure," Zagala said.

The Abu Sayyaf, which is on a U.S. list of terrorist organizations, was founded in 1991 on Basilan island with funds and training believed to come from Asian and Middle Eastern radical groups, including al-Qaida. It came to U.S. attention in 2001 when it kidnapped three Americans, one of whom was beheaded, along with dozens of Filipinos.

The group is still holding about a dozen hostages in the jungles of nearby Sulu province, including two European bird watchers who were kidnapped two years ago,

Zagala said Friday's operation is unrelated to the search for suspected Abu Sayyaf gunmen believed holding a 28-year-old Chinese tourist abducted last week from a Malaysian resort off Borneo island.