Manila - Communist rebels attacked a provincial jail in the southern Philippines in a bid to free a detained comrade, but the attempt was foiled by security forces, the country's military said Thursday.

The guerrillas on Wednesday fired three mortar rounds at the jail in General Santos City in Sarangani province, 1,050 kilometres south of Manila.

Major Armand Rico, a regional military spokesman, said an initial investigation showed that the attack was "intended to spring a communist rebel personality jailed" in the facility.

Soldiers and police, backed by two armoured vehicles, responded to the attack within minutes, forcing the rebels to withdraw without freeing their detained comrade, Rico said.

No casualties were reported, he said.

Police set up checkpoints around the jail for additional security, he added.

Communist rebels have been fighting the Philippine government since the late 1960s, making the movement one of the longest-running leftist insurgencies in Asia. (dpa)