Thai Prime Minister Surayud Chulanont has blamed ousted politicians for a series of bomb blasts in Bangkok that killed three people and injured 38.
At least eight blasts rocked Bangkok on New Year's Eve
Mr Surayud did not name anyone, but pointed the finger at "all those which have lost power in the past".
Mr Surayud was appointed by the military after it forced Thaksin Shinawatra from office in September.
The government cancelled Bangkok's New Year celebrations and called an emergency meeting on the attacks.
Mr Surayud said on New Year's Day that intelligence agencies had suggested the blasts were the work of "groups that have lost political powers".
"These were not just the previous government, but include all those which have lost power in the past. We could not at this stage pinpoint which particular group was involved," he said.
Mr Surayud declined to say what evidence pointed to former politicians, but he said it was unlikely that Muslim militants, who have carried out attacks in the south, were to blame.
Mr Thaksin's lawyer, Noppadol Patama, told the website of a Thai newspaper that the former PM was in China and was not involved in the blasts.
The BBC's Jonathan Head in Bangkok says normal life has returned to the capital, with traffic able to move through areas blocked off by police after the explosions.
Security has been increased in key locations such as the international airport.
The first spate of six attacks occurred across Bangkok as streets were filling up late afternoon on New Year's Eve.
Just before midnight, at least two further blasts rocked the city centre.
Two people died on Sunday, and a third man died of his injuries on Monday in hospital. All three victims were Thai.
Several foreign tourists were hurt. Two British men, three Hungarians, two Serbs and an American were receiving hospital treatment but none were thought to be in a serious condition.
The largest attack was near a bus station next to one of Bangkok's busiest intersections, Victory Monument.
Police said this caused the biggest number of casualties, injuring at least 13 people and killing one.
Reports suggest the device was planted beneath a seat at a bus stop or in a rubbish bin.
According to a police spokesman, the other blasts occurred:
- At 1720 on Sukhumvit Road in the south-east, causing no casualties
- At 1800 at a crossroads in the north, injuring two people, and simultaneously in Kae Lak district, injuring no-one
- At 1830 close to a Chinese temple in the Klong Toey district, killing one person and injuring six
- In a rubbish bin near the Seacon Square shopping area, injuring no-one