The Centre for the Resolution of the Emergency Situation on Friday issued a series of instructions on improved security after reviewing the police report on the Soi Rang Nam explosion caused by the firing of M-79 grenade.
"The M-79 grenade launcher was used in the attack on Thursday's night and the police were trying to pinpoint from where the projectile was fired," CRES spokesman Colonel Sansern Kaewkamnerd said.
The CRES was chaired by Deputy Prime Minister Suthep Thaugsuban and its participants included Defence Minister Prawit Wongsuwan and top military leaders.
At the meeting, Prawit suggested for checks on security cameras if the forensic bomb squad could not determine the exact launching point of the grenade.
This prompted Suthep to instruct the Bangkok Metropolitan Administration, with jurisdiction over the security cameras, to assist police in the investigation and to ensure the security equipment installed by the city was in working order as a precaution for future attack.
He also ordered police to strengthen security measures in the capital in the face of the Sunday's vote for city councillors.
In one of the leads, investigators have suspected the grenade attack might be motivated by the vote.
Metropolitan Police commissioner Lt General Santhan Chayanont said the preliminary forensic chec indicated that the grenade might be fired from the direction of Sri Ayutthaya Road to the ground of King Power complex fronting Phyathai Road's Soi Rang Nam.