A series of coordinated bomb attacks stunned the Thai capital as it prepared to ring in 2007, killing two people and canceling festivities for thousands of revelers. Investigators spent New Year's Day trying to determine who was behind the attack.

The nine bombs that exploded across Bangkok on New Year's Eve and early Monday also wounded 34 people — at least six of them foreigners.

The bombings capped a year of unrest in Thailand, including a military coup three months ago and an increasingly violent Muslim insurgency in the south.

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There was no claim of responsibility. National deputy police chief Gen. Ajirawit Suphanaphesat said Muslim separatist insurgents were probably not behind the attacks.

The foreigners known hurt were two Serbians, two Britons, a Hungarian and a U.S. citizen, said Suchila La-oan, a staff member of the Police General Hospital, where they were sent.

The bombings triggered a major security lockdown in the Thai capital, but no chaos. An investigation has been launched.

The three bombs that exploded just after midnight Monday were in a phone booth, a hotel, and near a canal bridge in a downtown area thick with heavily touristed hotels and shopping malls.

They went off near the planned venue for Bangkok's main New Year countdown party, canceled hours earlier after the six initial blasts throughout the city.

"Due to several bomb explosions in Bangkok and for the sake of peace and security, I would ask all of you to return to your homes now," Bangkok Mayor Apirak Kosayothin had told some 5,000 revelers at the downtown Central World Plaza shopping mall. The crowd dispersed quickly but calmly.

Hotels stepped up security, searching cars and canceling expensive New Year's Eve dinners.

"I heard a loud explosion and I thought it was fireworks. I ran there and saw a bleeding woman at the bus stop," said Somrak Manphothong, a receptionist at the Saxophone bar along a busy traffic circle near the Victory Monument, the scene of one bombing.

"Another guy was lying on the floor, covered with blood, and his wife was shaking his body," Somrak said.

At another site near a vegetable market in the Klong Toey slum, a pool of blood and egg yolks covered the roadside beside an overturned motorcycle.

The main public celebration was also called off in Thailand's northern hub city of Chiang Mai, though no incidents were reported there.

But New Year festivities continued in parts of Bangkok, with hundreds of foreign tourists still partying into the night in the famous Patpong Road red light district.

Fireworks lit up the sky at midnight in both Bangkok and Chiang Mai, with many people still gathered in the streets.

Police and army troops with assault rifles guarded some entertainment venues, mass transit stations and traffic circles. Roadblocks were set up on some streets.

Several foreign embassies responded to the bombing by issuing updated travel advisories, warning that the threat of terrorism was high and advising their citizens not to travel within Bangkok and to avoid mass gatherings.

"There is a possibility of further attacks in coming days," said a travel advisory from the Australian Department of Foreign Affairs and Trade.

The six earlier bombs wounded 14 people seriously, while the rest were treated and released from hospitals, said Health Minister Mongkol Na Songkhla.

The bombings came in the middle of a long holiday weekend during the peak tourist season in Bangkok, a city known for its easygoing, party-hearty spirit.

"No, I'm not scared. I'm from England. There are bomb scares all the time," said Keith Waters, who nevertheless expressed disappointment since he had been looking forward to ringing in his first New Year with his Thai wife.

The city has rarely experienced deadly bombings, although several small explosives were set off during recent political turmoil in an apparent attempt to create a sense of instability, not to cause casualties.

In September, a group of generals ousted Prime Minister Thaksin Shinawatra in a bloodless coup, and the military installed Surayud Chulanont as interim prime minister until elections set for October 2007.

Thaksin still has widespread support, and a number of arson attacks in provincial areas have been blamed on his followers.

"There are two potential suspects: Muslim insurgents and Thaksin's residual power. I tend to think it's residual power. I suspect the previous regime," said Thitinan Pongsudhirak, a political scientist at Chulalongkorn University.

"The coup was not done right," he said. "If there had to be a coup, they had to put away Thaksin and his cronies."

Thaksin's lawyer, Noppadol Patama, was quoted on the Matichon newspaper's Web site as saying that Thaksin was in China, and not involved in the bombings.

"Thaksin carries out only his political work," the lawyer said. "He doesn't do such things. If he wants to spark any movement, he won't use violence."

Bombings and shootings occur almost daily in Thailand's three southernmost provinces of Yala, Narathiwat and Pattani, where an Islamic insurgency that flared in January 2004 has killed more than 1,900 people.

The insurgents have carried out numerous attacks in the south, but are not known to have launched any in Bangkok.

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