Thailand's powerful military council on Wednesday declared that Sunday night's bomb attacks were staged by politicians and renegade army officers loyal to exiled Prime Minister Thaksin Shinawatra who want to topple the government.
It vowed to severely punish those behind the bombings, which killed three people and wounded nearly 40 while the city was in the midst of New Year's celebrations.
"We will bring the culprits to justice," said Surayud Chulanont, the interim prime minister appointed by the military, which ousted Thaksin in a bloodless Sep. 19 coup.
However, no evidence has yet been made public linking anyone to the bombings, and there is still speculation that it could have been the work of Islamic separatists who have been carrying out a bloody insurgency in the country's southernmost provinces that has claimed almost 2,000 lives since 2004.
The authorities received hundreds of calls Wednesday reporting suspicious packages or warning of bombs, though no actual explosive devices were found.
Places affected included a school, a downtown luxury shopping center, at least one bank, an Air Force base and the offices of the English-language newspaper The Nation. Several were evacuated while police conducted searches. The bomb scares came on the first working day after the long holiday weekend.
Police issued a warning that people making false reports about bombs would be prosecuted, while Surayud instructed the Information and Communication Technology Ministry to install closed-circuit cameras throughout Bangkok and told security agencies to tighten security at airports and bus and train terminals throughout the country, reports AP.
"The evidence and intelligence information proves that the bombs were the dirty work of politicians who lost power and benefit. Some bad soldiers loyal to the bad politicians collaborated with them with the intention to topple this government," said Gen. Saprang Kanlayanamitr, a member of the Council for National Security.
He said that the days of compromise with the former power-brokers were over and "from now on there will be no compromise." Since staging the coup, the military has repeatedly claimed that Thaksin's supporters are trying to create political instability to set the state for a comeback.