Six people were killed and more than two dozen wounded when a bomb exploded at a restaurant in the southern Philippines, police and local officials said on Saturday.
Police said the improvised explosive device went off around midnight (1600 GMT Friday) at a popular restaurant in the southern port city of Cagayan de Oro.
The motive for the blast was not immediately clear, Cagayan de Oro police chief Graciano Mijares said.
"We will have to wait for the results of the investigation," he added.
Cagayan de Oro is located on the main southern island of Mindanao, which has been blighted by a decades-old rebellion by elements of the large Muslim minority in the mainly Catholic Asian nation.
Local businessman Noel Arcenas, who owns an electronics shop at the shopping complex where the restaurant is located, said at least 100 people were inside the popular establishment when the explosion occurred.
"I felt then heard the blast," said Arcenas, who added he was standing about 15 meters (49 feet) away.
"I looked around and saw this ball of white smoke. People were running away bloodied and survivors were dragging at least seven or eight people away from the blast site."
The powerful explosion broke glass panels, upturned tables and chairs, and damaged cars parked up to 30 metres away, reporters at the scene said.
The six dead included local politician Roldan Lagbas, a member of the provincial executive board of Misamis Oriental province, police said.
Twenty-eight people were wounded, many of them representatives of pharmaceutical companies who were having a party at the restaurant, police added.
Cagayan de Oro Mayor Oscar Moreno told ABS-CBN television network that at least two of the wounded were in critical condition.
"Doctors have been attending to them and we hope their situation will stabilise soon," Moreno told the station.
Asked who he thought was responsible for the attack, he said: "It's hard to speculate at this time."
Muslim groups including the Moro Islamic Liberation Front (MILF) have waged a guerrilla war for a separate Islamic state in Mindanao since the 1970s, a conflict that has claimed an estimated 150,000 lives.
President Benigno Aquino's government and the MILF signed a preliminary deal in October last year outlining the broad terms for a peace treaty that is expected to be signed before he ends his six-year term in 2016.