Digos: A bomb blast ripped through a bus terminal in southern Philippines on Monday, killing at least six people and injuring 27 others, police said.

Davao del Sur police chief Cesario Darantinan said the bus was parked at the terminal in the town of Digos when the explosion occurred.

"It could have been a crude bomb that was set off remotely," Darantinan said. "The explosion was so powerful that the bus was almost broken into two."

Police earlier said four people were killed on the spot. Two  people later died in hospital, raising the death toll to six.

Police said it was the second bomb attack on a bus since last month, when two people were killed in a similar attack.