Ensign Chester Ramos, a spokesman for "anti-terrorist operations" Joint Task Force Zambasulta -- Zamboanga, Basilan, Sulu, and Tawi-Tawi -- confirmed that the eight died and 13 soldiers were injured in fierce fighting in a village in Patikul around midday.
He said that the soldiers figured in a fight with about 100 heavily armed Abu Sayyaf, led by group leader Radulan Sahiron, and two sub-leaders -- Hairulah Asbang and Amlon Abtahi.
"The Air Force provided close air support to the troops," he told reporters. "We are doing all-out law enforcement operations in Sulu since October following the release of the German captives."
In October, German hostages Stefan Viktor Okonek and Herike Diesen were released by the group, which has claimed it was paid a P250 million ($5.5 million) ransom. The government, however, has maintained no payment took place.
On Thursday, two Abu Sayyaf were killed in a clash that left seven others -- including four soldiers -- wounded in Sitio Kan Udang in Barangay Taglibi, also in Patikul town.
Since 1991, the Abu Sayyaf -- armed with mostly improvised explosive devices, mortars and automatic rifles -- has carried out bombings, kidnappings, assassinations and extortion in a self-determined fight for an independent Islamic province in the Philippines.
It is notorious for beheading victims after ransoms have failed to be paid for their release.