BANGKOK, Thailand (AP) -- Airports in southern Thailand went on full alert Monday after bomb blasts at the region's main airport and two other sites killed at least two people, wounded more than 70 and raised concerns that Muslim insurgents were expanding their reach.
Several foreigners were among the wounded in the blasts late Sunday at three locations in Songkhla province: the Hat Yai airport that serves as the main gateway to Thailand's far south, a department store and a hotel.
They were the first major attacks outside of Thailand's three southernmost provinces where an Islamic insurgency has raged since early last year, claiming almost 800 lives. Songkhla is just north of that region.
''We have to check the security at all airports and railway stations in southern Thailand,'' Deputy Minister of Transport and Communications Phumtham Wechayachai told reporters Monday.
The explosion at the Hat Yai airport killed two people, Songkhla Gov. Somporn Chaibongyang said. Another bomb exploded at the city's Carrefour department store and a third bomb exploded in front of a hotel in the city of Songkhla, on the Gulf of Thailand coast not far from Hat Yai.
The Public Health Ministry said 74 people had been injured in the blasts, including an American woman, a French woman and two people from Brunei.
Initial investigations showed that the powerful blasts were triggered by mobile telephone signals, military spokesman Lt. Gen. Palangoon Kraharn said.
Prime Minister Thaksin Shinawatra condemned the explosions and expressed his condolences to the victims. He said security in the south had to be strengthened, but declined to say whether the government would implement any tough new measures.
''We are working toward unity,'' Thaksin said. ''As for prevention and suppression, we have to work intensely, and we won't leave behind peaceful methods.''
Thaksin has been criticized previously for adopting an iron-fist policy that critics said would only breed more insurgents. However, he has recently called for a more measured approach that would de-emphasize military action.
Television footage showed dazed and bloodied people at Hat Yai airport being treated by paramedics late Sunday.
The airport bomb was left in a bag by an unidentified man in the waiting area, said Gen. Chaiyasit Shinawatra, the Thai military supreme commander. The bomb at the Dream World Hotel was hidden in a motorcycle, police said.
All three explosions took place between 8 p.m. and 8:30 p.m., officials said.
No one claimed responsibility for the blasts, but they were likely linked to the insurgency in Thailand's Muslim-dominated southernmost provinces. The bombings were the first major attacks outside the provinces of Narathiwat, Yala and Pattani, where shootings or small bombings have occurred almost daily since January of last year.
The sophistication of recent attacks has raised questions about whether the insurgents are getting outside assistance.
Thai authorities acknowledge that local insurgents have had contacts with the regional terrorist organization Jemaah Islamiyah, but deny there is significant foreign influence.
Jemaah Islamiyah, which is loosely linked to al-Qaida, has carried out several major bombing attacks in Indonesia in the past three years.
