ILIGAN CITY, Philippines--(UPDATE 2) Police authorities defused on Sunday another improvised explosive device (IED), three days after three people were killed and 46 others were wounded in explosions that ripped through two stores here.

The fourth bomb was discovered by scavengers among a pile of garbage on a vacant lot between San Miguel and Burgos Streets here around 10 a.m. Two military officials were issuing assurances to residents that the city would have a peaceful Christmas.

As with the bomb left by two unidentified men inside the Delecta Bread Shop in Palao, a few hours after President Gloria Macapagal-Arroyo left on Thursday, Sunday's find was also inserted inside a papaya fruit, according to Senior Supt. Celso Regencia, officer-in-charge of the city police office.

Regencia described the unexploded IED as fashioned out of an 81-millimeter mortar shell.

"We immediately called the Explosive and Ordnance Division of the Philippine Army, Special Action Force of the Philippine National Police and the K-9 team. They defused the bomb," Regencia said.

A military intelligence officer, who refused to be identified, said the mortar shell was different from those issued to the military.

Except for saying it was an "imported one," he declined to elaborate.

The discovery of the bomb took place while Col. Nicanor Dolojan of the Army's 403rd Infantry Brigade, and Col. Benito del Leon of the Army's 104th Infantry Brigade, were being interviewed over the radio by members of the Lanao Press and Radio Club.

The venue of the interview was only about 150 meters from where the bomb was found.

Informed about the find, the two officers said those behind the bombings were cowards who targeted civilians.

But they issued assurances to the public of a peaceful Christmas in the city.

Meanwhile, peace advocates asked authorities to "go slow in pointing the blame" at Moro rebels for Thursday's blasts here.

Hadji Abdullah Dalidig, chair of the Muslim Multi-sectoral Movement for Peace and Development (MMMPD), said "prematurely ascribing responsibility" to a particular group would be "a disservice to the ends of justice."

"It is best not to pronounce who was really responsible until conclusive evidence had already been established," he said.

Dalidig said they were worried that the "immediate dragging" of the Moro Islamic Liberation Front (MILF) into the picture could further scuttle recent efforts to restart the peace negotiations.

Chief Supt. Teodorico Capuyan, Northern Mindanao police director, told reporters Friday that bomb experts probing Thursday's blasts found fragments of a nine-volt battery and wires from the scene.

Capuyan said it meant that the two bombs were timer-detonated.

The military said bombs planted by groups linked to the MILF in Central Mindanao in recent days were also fitted with timers.

Lt. Gen. Nelson Allaga, chief of the Western Mindanao Command, said the similarity drove them to conclude that the rebel group had a hand in the Iligan explosions.