At least 26 people have died in a battle between Philippine marines and the Abu Sayyaf group, after its fighters attempted to regain control of a captured jungle encampment.

Military officials said on Wednesday that about 100 Abu Sayaff fighters mounted their assault on the camp, in a mountain area near Patikul in the southern Sulu province, late on Tuesday. One marine and 25 Abu Sayaff fighters were reported killed, and dozens were injured.

"They tried to overwhelm our marines to regain their camp but we have back-up forces nearby and close air support,'' said Captain Ryan Lacuesta, a miliary spokesman. "They resorted to mortar and rifle grenade fire so our wounded mostly were hit by shrapnel."

The well-fortified Abu Sayyaf encampment was used by the group for training, meetings and as a staging area for attacks and kidnappings, said Brigadeer General Martin Pinto, a marine commander.

Abu Sayyaf, which is on a US list of "terrorist organisations", has conducted bombings, extortion, kidnappings and beheadings, and has targeted foreign missionaries and tourists in the south.

An estimated 300 fighters, who are split into several factions, still hold several hostages in their Sulu jungle bases, including two European bird-watchers abducted two years ago.

A Chinese tourist and a Filipino hotel worker who were recently kidnapped in Malaysia's Sabah state are also thought to be being held in Sulu.

Huge ransom payments have allowed Abu Sayyaf to survive and finance attacks despite Philippine military offensives.

Source: AP