Three bombs disguised as cell phones were defused at a Philippine shopping mall in General Santos. Designed to cause fires, the motives included extortion, a business rivalry and an attack by militants.

"Vigilant sales staff alerted us about the bombs after a mobile phone was found in the pocket of a pair of pants on display," said Chief Superintendent Antonio Billiones, police chief of the southern part of Mindanao.

Bomb-sniffing dogs found two similar devices on the second floor of the KCC mall in General Santos, hidden under stacks of shirts and jeans in the menswear section.

This follows three attacks on February 14, claimed by Abu Sayyaf, a group of about 400 militants linked to al Qaeda. No group has claimed responsibility for the mobile phone bombs, which investigators said smelled of kerosene.