Southern Philippines police tighten security

Security forces went on full alert in the southern Philippines on Sunday, police said, after military intelligence reported sightings of Islamist militants in the region after the detention of a top al-Qaeda-linked leader.

Last week, a team of soldiers and police officers arrested Khair Mundos, an expert bomb-maker and the "spiritual leader" of the Abu Sayyaf faction, which rose to notoriety early last decade by kidnapping foreigners.

Mundos is wanted by the United States, which put a $500,000 bounty up for his arrest.

"Information received with high reliability revealed a possible terrorist threat to the peace and security of Region 11, particularly in Davao City," Chief Superintendent Reuben Sindac, national police spokesman, said in a statement.

"All police forces in Mindanao have already been alerted to beef up security operations against possible infiltration of suspected members of said reported threat groups."

President Benigno Aquino III called the Davao City mayor to relay the possible threat. Davao is the country's third-largest metropolitan area with a population of more than 2 million.

Local officials held a meeting on Saturday night with security officials to assess protection at shopping malls, parks and transport terminals.

Roadblocks were set up around Davao City. Patrols were also stepped up in General Santos, Cagayan de Oro, Kidapawan and Koronadal.

"We are preparing for possible retaliatory attacks from Islamist militants to avenge the arrest of Mundos," an army intelligence officer said, adding the presence of Islamist rebels was reported to them in Davao City a couple of days ago.

Abdul Usman Basit, brother-in-law of Khair Mundos, a member of the militant group's special operations unit, was seen in the city. He trained under Malaysian bomb-maker and Jemaah Islamiah leader Zulkifli bin Hir or Marwan, also on the US terrorist list.

Marwan has a $5 million bounty from the US State Department for his arrest, while Basit Usman has a $1 million bounty. Both were earlier reported killed in air strikes, but they survived with some injuries.