At 9pm a grenade landed in the Daily News compound, between the offices of the newspaper and Daily News TV.
The explosion made a small hole in the ground and damaged an air conditioner compressor and a building pillar.
A witness said he heard an explosion and saw thick smoke. He first believed that the explosion has come from the aircon compressor but later learned that it was a bomb.
The CCTV footage captured the moment when the grenade exploded.
Police believed the assailants may have shot the grenade from behind the newspaper compound.
At around 10pm, an M-79 grenade was shot into the compound of the Administrative Court near the anti-government protester site in the Chaeng Wattana area.
It landed in a bush near the entrance gate.
The witnesses said they saw the grenade being fired from a pickup truck passing the CAT Telecom office.