One person was killed and 37 injured Friday when a suspected bomb exploded outside a bus depot in the southern Philippine port of Zamboanga, the city mayor said.
Mayor Maria Isabelle Climaco told ABS-CBN television by telephone that local authorities suspected the al-Qaeda-linked armed group Abu Sayyaf was behind the attack.
She said the explosion may be part of a plot by the Abu Sayyaf, which has been blamed for the deadliest bombings to hit the Philippines, to break 57 of their comrades out of the Zamboanga city jail.
"We have received notices (from the intelligence community) that they are going to be rescued by their comrades, who are ready to die," Climaco said.
The Abu Sayyaf, a loose band of a few hundred militants founded with seed money from Al Qaeda, has been blamed for the worst terror attacks in Philippine history.
These have included the bombing of a ferry in Manila in 2004 in which more than 100 people died, and repeated kidnappings of foreigners in the southern Philippines who are usually ransomed off for huge amounts.
Today's blast tore through a vehicle parked near a bus terminal and "left a crater" beneath it, Climaco said, adding that she had asked the justice department to transfer the "high-value" prisoners outside the city.
Many foreign governments warn their citizens against travelling to the southern Philippine areas, including Zamboanga, which are regarded as strongholds for the Abu Sayyaf and other Islamic militants.
The Abu Sayyaf claims it is fighting to establish an independent Islamic homeland in the Muslim populated south of the mainly Catholic Philippines.
Zamboanga was attacked by another Muslim armed group loyal to former Muslim rebel leader Nur Misuari in September 2013.
The attack triggered three weeks of street battles that left more than 240 people dead and large parts of the city of nearly one million in smouldering ruins.
During the fighting, in which the rebels also used civilians as human shields, about 10,000 homes were destroyed by fires, forcing 116,000 to flee.
