A blast in the southern Philippines has killed at least eight people and injured more than 40 in what police suspect was an assassination attempt on a town mayor.

The bomb attack happened late in the afternoon on Sunday in Parang, in the southern Philippine province of Mindanao. It ripped through a crowd gathered to watch a basketball game. The death toll was expected to rise, as dozens of seriously injured people were taken to area hospitals.

Avelino Razon, the operations director for the Philippines National Police, said the bombing may have been an assassination attempt on Vivencio Bataga, the mayor of Parang. He was injured in the attack, but survived. "It was not a suicide bomber, it was a bomb that was placed in a motorcycle, a 60-millimeter mortar rigged, which was left beside the gymnasium. They are looking [to see] if this is an attempt on the life of Mayor Bataga," he said.

Mr. Bataga is a Christian mayor of the largely Muslim town. Authorities are not ruling out the possibility that Muslim separatists operating in Mindanao planned the attack.

The province has seen more than three decades of violence over guerilla attempts at establishing a separate Islamic state.

Mayor Bataga has survived several attempts on his life in the past. He had just finished delivering a speech when the bomb went off.

The attack could also be related to the country's coming elections. Ballots are often marred by violence and attempts at intimidating voters.