No one was hurt in the blast at the police's Camp Bagong Diwa in Taguig City in Metro Manila on Monday, but the attack caused embarrassment to government security forces.

''We saw that there were security lapses in Camp Bagong Diwa,'' said Chief Superintendent Juan Urani, a regional police commander.

Urani identified the relieved officers as Superintendent Innocentes Capuno, security officer of Camp Bagong Diwa, and Chief Inspector Paulino Logronio, chief of the police unit supervising the camp.

The explosion was caused by a homemade device made from TNT, which was planted in a SWAT van parked inside the police camp. No one was hurt in the blast.

Camp Bagong Diwa houses the headquarters of the Manila police force and a maximum security prison compound where high-profile criminals and suspected terrorists are detained.

It was the sixth small bomb attack claimed by a shadowy group called Masses and Soldiers in the past two weeks. The group is calling for the ouster of President Gloria Macapagal Arroyo.

Authorities said the attacks were being carried out to embarrass the police and the Arroyo administration, while causing little damages and casualties.

Previous targets included a police van, a police outpost and a house owned by a suspected gambling lord who is a known political ally and friend of Arroyo.