However, Metro police Director Avelino Razon Jr. pointed out that the bomb discovered at the 15th floor of the Octagon building on San Miguel Avenue had no blasting caps to trigger or detonate the explosive device.
"It was just meant to scare and not to hurt," Razon said.
The bomb was discovered by a janitor at the comfort room at the 15th floor at about 4 p.m.
He immediately called the police.
Members of the responding Explosives and Ordnance Division of the Eastern Police District (EPD) retrieved a shoebox near the toilet. It contained a crystalline substance, a watch and several wires.
After 30 minutes, the EOD team removed the device from the premises.
Police said they did not evacuate the building, which houses several commercial establishments. K-9 teams made a sweep of the entire building, but found no similar devices.
Razon dispelled rumors that the bomb was linked to the threats of the Abu Sayyaf to avenge the death of their 22 comrades killed in last Tuesday’s assault at a detention center in Bicutan, Taguig.
The Abu Sayyaf had vowed to mount retaliatory bombings in Metro Manila.
The Metro police chief directed Chief Superintendent Oscar Valenzuela, EPD director, to investigate the incident.