COTABATO CITY, Philippines—Authorities disabled a bomb in Shariff Kabunsuan two days before President Gloria Macapagal Arroyo was to arrive for a meeting on security concerns in Central Mindanao.

Police said they foiled the terror plot after discovering the bomb in a store in Datu Odin Sinsuat town.

The discovery came two days before Arroyo was to meet with officials of the defunct province and military officials on mounting security concerns in the region.

The Supreme Court had declared unconstitutional the law creating Shariff Kabunsuan, which effectively reverted its towns to Maguindanao, the mother province.

Chief Inspector Dante Mama, Datu Odin Sinsuat police chief, said the bomb was found in the village of Awang on Monday near the military headquarters that Arroyo was scheduled to visit Wednesday.

Unidentified men left the bomb in front of a store that was just about 30 meters from the camp, said Mama.

The Cotabato airport is also near the Army’s 6th Infantry Division headquarters in Awang.

Superintendent Esmail Ali, of the Maguindanao provincial police office, said the bomb, which he described as powerful, was placed inside a sealed plastic bag.

"It caused panic among commuters and passersby," he said.

Ali said traffic had to be rerouted before experts defused the bomb.

Mama said the bomb was unlike previous explosives found elsewhere.

He said the bomb found on Monday in Awang had no timing device but there was a cord that once pulled or accidentally touched by anybody, could trigger the mechanism.

Mama said investigators theorized that the bomb was intended for other areas, which means it had nothing to do with the President's visit.

"Its courier might have been forced to abandon it there due to tight security," he said.

The bomb was the second recovered in Maguindanao this month.

Last week, Army soldiers also found an improvised explosive device strapped onto a bridge in Labu-Labu village in Shariff Aquak.

In recent days, bombs had also exploded or were defused in some areas of Central Mindanao, which is near Maguindanao.

The military has blamed Moro rebels for some of the explosions and bomb plots while saying some could be the work of extortion groups.