MANILA, Philippines - Tension gripped the regional trial court in Sta. Cruz, Laguna after security personnel found an improvised explosive device inside one of the offices Wednesday morning, police said.

Superintendent Marvin Saro, Sta. Cruz police chief said, 2 security guards manning the RTC building noticed smoke billowing from the Office of the Clerk of Court around 2:30 a.m.

Saro said the guards immediately entered the room and found an improvised explosive device packed in a small red box with a cellular phone as the triggering device and a lighter fluid.

“Inilagay iyong bomba sa ilalim ng istante na may mga old files, possibly with the intention of burning it,” Saro said.

Crime scene investigators said the firebomb had been triggered, but it failed to explode.

Police said none of the court’s files or facilities were destroyed and no one was injured.

A sweep by explosive and ordnance personnel at the regional trial court for more bombs turned out negative.

Investigators have yet to determine the motive of the failed arson and the people behind the attempt. The incident prompted court officials to suspend hearings and transactions.