Bombs have exploded in two southern Philippine cities killing at least six people and injuring dozens more.
There is a visible police presence in Cebu ahead of the summit
The fatalities occurred as a bomb was detonated in General Santos city. Hours later, an explosion in Kidapawan city, 110km further north, wounded others.
The blasts came as the authorities stepped up security ahead of this weekend's summit of leaders of 16 Asian nations in the central city of Cebu.
The foreign secretary said the meeting would go ahead despite the attacks.
"I have been told by our security people that everything is safe and secure here... and therefore the show will go on," Foreign Secretary Alberto Romulo said.
Police said at least six people were killed and 26 wounded in a blast around dusk in a crowded market in General Santos city, a major port 400km (250 miles) south of Cebu.
A few hours later, an explosion in Kidapawan city, also on Mindanao Island - an area targeted by Islamist militants in the past - wounded at least two people.
No-one has yet claimed responsibility for the bombings but Philippine authorities said they suspected Muslim militants, saying they may have been trying to embarrass the government ahead of the Association of South East Asian Nations (Asean) summit.
The attacks come amid stepped-up military offensives against Abu Sayyaf and Jemaah Islamiyah rebels, both said to be linked to al-Qaeda, on the nearby island of Jolo.
The bombings also occurred as government peace negotiators held two days of talks with the Moro Islamic Liberation Front (MILF), the main separatist group in the south.