Thailand is on alert over the Thai New Year, or Songkran, holiday for further bombings in Bangkok with security stepped up nationwide. As Ron Corben reports from Bangkok, the usual festive atmosphere has been shrouded by the country's political uncertainties and memories of bomb blasts in December in the city that claimed three lives and injured dozens.

Thailand's week-long Songkran holidays are marked by tens of thousands of people traveling to their hometown or to resorts at the peak of the Thai summer.

But this year's festivities lie in a shadow.

There are fears that violence from a separatist insurgency in the country's south could spread to Bangkok or other urban centers. In addition, protests against the military-led government have been growing. The military ousted Prime Minister Thaksin Shinawatra last September, and both Mr. Thaksin's supporters and some of his opponents, are demanding that elections be held.

A small explosion outside a movie theater earlier this week added to tensions. Although no one was hurt, the bombing refreshed memories of eight bomb blasts on December 31 across the city that left three people dead and more than 20 injured.

The city government and the police are stepping up security for the traditional Thai New Year, which begins today and continues into next week. Check points have been set up in Bangkok and in some areas, residents are warned not to engage in the tradition of throwing water on people.

Buranaj Smutharaks is a spokesman for the city government. He says improving security has been a priority since the December 31 blasts.

"If anything it will be heightened as time goes on," he said. "There is really no going back to the state of less alertness. In terms of Thailand we are very quickly now installing closed circuit cameras in all the major public areas. And this level of vigilance will continue."

Police have doubled patrols in Bangkok, with three thousand officers in the field and one thousand on stand-by. An extra 40 thousand police are deployed across the country over the holiday.

Police Lieutenant General Jongrak Jutanont leads the investigations into this week's blast. He says he is confident the extra security will prevent more bombings over the holiday.

"In Songkran, no bomb, no bomb," he said. "Many Thai police on duty, on the street, and any place for the people for safety. I think everything is ready in Songkran. The last bomb is no danger. I think everything is ready on Songkran."

The security threat has led embassies to renew travel alerts to their nationals coming to Thailand.

Security concerns have already cut the number of tourists. Arrivals from Japan are down by as much as 10 percent since December.

However, some tourists, such as this Briton, are encouraged by the stepped-up security effort.

"We don't feel at all threatened. There's obviously you can see more security," he said. "When you go in an out of shopping complexes you actually have your bags checked which is a good idea. But there is a limited amount of things that people can do. If the thing is going to happen, it will happen."

Thailand faces one of its most testing political periods in recent history, as the government copes with the southern insurgency and public frustration with the military's leadership. For many Thais marking Songkran this year, there will be wishes of better times ahead.