Abu Sayyaf militants behind Philippine bombing: mayor

The Abu Sayyaf Islamic militant group carried out a bomb attack in Philippine President Rodrigo Duterte's home town that killed at least 14 people, the city's mayor said Saturday.

"The office of the president texted and confirmed that was an Abu Sayyaf retaliation. For the city government side, we are working on that it is an Abu Sayyaf retaliation," Sarah Duterte, who is also the president's daughter, told CNN Philippines.

National Defence Secretary Delfin Lorenzana also released a statement saying he believed the Abu Sayyaf, which in recent years has declared allegiance to the Islamic State group, carried out Friday's bombing on a bustling night market.

"While nobody has come up to own the act we can only assume that this was perpetrated by the terrorist group Abu Sayyaf that has suffered heavy casualties in Jolo in the past weeks," Lorenzana said.

"We have predicted this and has warned our troops accordingly but the enemy is also adept at using the democratic space granted by our constitution to move around freely and unimpeded to sow terror."

Duterte last week ordered a major assault against the Abu Sayyaf on its stronghold of Jolo island, about 900 kilometres from Davao. Fifteen soldiers died in clashes with the Abu Sayyaf on Monday.

National police chief Ronald dela Rosa told a briefing in Manila that the Abu Sayyaf was a top focus of investigations, although he did not definitively lay the blame on the group, saying other leads were also being followed.