MANILA, Philippines – A suspicious-looking paper bag abandoned inside a bus caused tension in Manila on Tuesday morning.

The Manila Police District said the bag was abandoned at the back portion of Tas Trans bus along Liwasang Bonifacio in Lawton, Manila.

Passengers were alarmed after seeing some wires sticking out of the bag.

Bomb experts carefully opened the bag, only to discover that it was filled with sand.

Police said the person who left the bag really had an intention to scare people as a note was also found attached to it, saying: "'May iniwan akong bomba sa ilalim ng upuan ng bus ninyo. Huwag kayong gagawa ng anumang ingay o gulo upang mapansin ng mga pasahero ninyo. Gusto ko ihinto ninyo ang bus sa tapat ng Post Office at tumawag kayo ng mga pulis... Huwag ninyong subukang kunin at itapon ito dahil isang pindot lang 'Boom' Baguhin ang Pilipinas."

Tas Trans, meanwhile, admitted it had received a letter threatening to bomb one of its units.

Authorities said it will look into the possibility that some disgruntled employees of the bus company were behind the bomb hoax. – report from Jeff Canoy, ABS-CBN News