Three bombs exploded almost simultaneously at an airport, a supermarket and a hotel in Thailand's restive Muslim south tdoay, killing one person and wounding more than 50 others.
The bombs, two of which were in the southern commercial town of Hat Yai, were the latest attacks in a region where more than 600 people have died in 15 months of violence the government blames on Muslim separatists.
Security officials said Islamic militants were behind the blasts and added they anticipated more attacks in the area, which lies just north of the three southernmost provinces of Pattani, Narathiwat and Yala, which have seen the worst of the violence.
"There will be more coming," a top security official told Reuters, adding that they had received word in advance of possible attacks in Hat Yai, but did not know where exactly and when.
Army Commander-in-Chief Pravit Vongsuvan told Channel 9 television militants had moved their operations further north because "our operations in the three provinces have been so effective that they had to move their works elsewhere."
The airport attack left one person dead. Hospital officials said a French tourist was among the injured.
Troops and police sealed off the airport and cancelled all flights as they went about defusing two more suspect items of luggage left in the parking lot and passenger hall.
Another eight people were wounded when a second bomb exploded at a Carrefour superstore, about 20 kilometres from the airport, seriously wounding five people.
A Hat Yai hospital official said they were treating more than 30 wounded from the two blasts.
A third bomb hidden in a motorcycle exploded outside a hotel in the town of Songkhla, 40 kilometres north of Hat Yai, but there no fatalities.
Security at other airports in southern Thailand popular with foreign tourists, such as Phuket and Krabi, had been tightened, officials said.
Buddhist Thailand's predominantly Muslim far south has a century long history of often violent separatism, which security analysts fear might attract backing from international Islamic militant networks.