ZAMBOANGA CITY -- A powerful improvised explosive device was recovered and detonated before President Gloria Macapagal Arroyo's visit to Sulu Thursday, a military official said.

Arroyo flies to Jolo for the Bishops-Ulama Conference interfaith assembly.

Colonel Eugenio Clemen, commander of the 3rd Marine Brigade, said the bomb was recovered and detonated four days ago near an area being occupied by workers of the Growth with Equity in Mindanao (GEM).

GEM is a US-funded program implementing infrastructure and social works in the island-province, which is known for being the hotbed of the Abu Sayyaf and the Moro insurgency.

It wasn’t known if Arroyo will also be visiting the GEM area.

"We were able to detonate the bomb, it's an improvised one, quite big and could generate great impact and destruction if it was not recovered," Clemen told the Philippine Daily Inquirer, parent company of INQUIRER.net.

He said a mechanical robot was destroyed when it was used to detonate the bomb, which he did not specify.

"We are confident President Arroyo's visit is safe because we also apprehended a suspected bomber responsible for the planting of the said bomb over the weekend," Clemen said, referring to Almid Jundam.

Jundam was arrested while trying to withdraw money from a bank on November 18.