An improvised explosive device (or some believe to be a grenade) exploded at the Jolo wharf today, while US troops were reportedly unloading equipment from a boat. Major Ramon David Hontiveros, spokesman for the Philippine military's Western Mindanao command said the blast occurred late Monday.

Hontiveros denied reports that the blast was caused by a powerful EID since no bomb fragments were found. The explosion happened near a military detachment adjacent to a building where stalls are selling electronic appliances and textiles. No one was hurt in the explosion.

What was worrisome were some accounts alleging that US troops reportedly fired upon civilians shortly after the bomb went off. Automatic gunfire hit a nearby mosque and small buildings. Civilian sources say, US troops indeed opened fire and bullet holes are still seen in the area.

This was denied by the military. The US embassy has yet to release an official statement regarding the incident.

US troops have been stationed in Jolo for many years now. They have a base inside the Jolo Military camp, but is off-limits to Filipino soldiers.

The AFP has since denied US troop involvement in the fight against the renegade terror group, the Abu Sayyaf. However, the Philippine defense department admitted that US troops have provided valuable intelligence information about the whereabouts of Abu Sayyaf Group members.

The Philippine Constitution prohibits the interference of foreign troops in local interacine or insurgency wars in its territory.