Delhi Police Commissioner B K Gupta today said that the bomb used in Monday's attack was not bigger than a palmtop or a brick.

He, however, said so far the investigations do not point to the use of RDX. He said the bomb would have exploded in 3-5 seconds after it was stuck on the vehicle. He added that the bomb could have been exploded using a remote or a timer.

As another attack was triggered in Bangkok, Gupta said Indian security agencies are seeking information from authorities in Georgia, where a bomb was defused, and Thailand.

On investigations, Gupta said, five persons were detained on suspicion but were let off after investigations. Gupta said Delhi Police was seeking CCTV footages from Israeli Embassy and Canadian Embassy that was close to the incident site.

Almost ruling out the hand of Indian Mujahideen in the attack, he said it could not be a normal terror module which one had witnessed here. He said police have recovered magnetic pieces and explosives.