Bangkok: Police in Thailand defused three unexploded bombs discovered in Bangkok and surrounding suburbs over a matter of hours, one of them in front of a school and one in a shopping mall, they said on Thursday.
The finds -- which come after a string of blasts in Bangkok -- have raised further doubts over the speed at which emergency rule can be lifted in the Thai capital and prompted opposition accusations of a government conspiracy.
One device was found under a footbridge outside a school in central Bangkok on Wednesday morning, Major General Prawut Thavornsiri, the national police spokesman, said.
Last night, two more, each weighing around five kilograms, were found at a shopping mall and in the Public Health Ministry car park in nearby Nonthaburi province, he added.
The Thai capital remains under emergency rule following deadly street clashes in April and May during anti-government protests.
Suthep Thaugsuban, deputy prime minister in charge of national security, said he had instructed officials to tighten security again after the three devices were found yesterday.
"This indicates that government opponents do not want our country to return to normal... Emergency rule is necessary to keep peace and order in Bangkok," he added.
But Jatuporn Prompan, a leader of the "Red Shirt" protest movement and an opposition lawmaker, said "all of the bombs are the work of the government" in an attempt to justify greater powers for authorities.
"The perpetrators did it because they do not want the state of emergency in Bangkok to be revoked and this act is aimed at creating a feeling that the special law is still needed," he told reporters.
Five grenade blasts in recent weeks, leaving one dead and 13 injured, have unnerved Bangkok residents still recovering from the unrest.
Suthep said a bomb hoax that emerged on Wednesday on a Thai Airways flight from Bangkok to Los Angeles was not related to incidents in the city.
On Friday, Thailand put over 460 locations across Bangkok on high alert, sending thousands of police, soldiers and city officials on to the streets to increase the security presence around the clock.
Royal palaces, government buildings, power plants and public transport are receiving protection from the Centre for Resolution of Emergency Situation (CRES), the body set up to monitor security in response to the unrest.