MANILA: A powerful blast ripped through a crowded popular nightclub in a southern Philippine city late on Friday, killing six people and wounding dozens, police said on Saturday, a reminder of the security challenges despite rising economic growth.

No one has claimed responsibility for the attack and an army spokesman said security forces are looking into a potential motive for the attack, including the possible involvement of communist rebels who are active in the area.

“Three people were killed on the spot from the blast,” said army spokesman Lieutenant-Colonel Leo Bongosia, adding three others including a local politician died in hospitals.

“We were shocked. We don't have this kind of attack in years.” Most of the blast victims were attending a medical convention organised by a local pharmaceutical company, were partying in a popular night club in Cagayan de Oro City when an improvised bomb exploded, Bongosia said.

The Philippines has registered the fastest economic growth in Asia in the first quarter, outpacing China. But long-running insurgencies from Maoist rebels and Islamist militants, with ties to Al Qaeda, remain in resource-rich areas outside Manila.