BANGKOK, Dec. 31 (UPI) -- Hours after six bombs marred New Year celebrations in Bangkok, a powerful explosion rocked the Thai capital's World Trade Center.

The bomb planted in a telephone booth injured at least one person early Monday, Xinhua reported.

Six bombs exploded in the waning hours of 2006, killing three people and injuring at least 30.

Among the sites targeted were a large shopping mall, a Chinese shrine, a supermarket, a pedestrian bridge and a bus station near Victory Monument.

Soldiers were deployed throughout the city as official celebrations and parties were canceled and department stores in downtown Bangkok -- usually open until midnight -- closed their doors early, Xinhua said.

Thai Prime Minister Surayud Chulanont asked revelers to avoid large gatherings and ordered an immediate investigation into the source of the bombs, local media said.

The Voice of America quoted Thai officials as saying Muslim militants, usually confined to the south of the country, were probably not behind the wave of bombings.