"Insurgents triggered the second bomb by mobile phone signal as police were about to defuse it, and it injured 19," Chob said.
Thaksin's assets frozen
Police officer Subin Pruekmongkol, who was severely wounded, was later pronounced dead in hospital, Chob said.
Muslims, who make up more than 90 per cent of the 2 million people in Yala, Pattani, Narathiwat and Songkhla complain of being treated as second-class citizens in mainly Buddhist Thailand
Area was semi-autonomous Islamic Malay sultanate until annexed by Thailand in 1902
Malay-Muslims complain assimilation policies have restricted their customs
Several violent uprisings have been put down by army over the century
Latest uprising flared in 2004 after three years of tough policies on the south by Thaksin Shinawatra, the then premier
Despite martial law imposed in 2004, near daily attacks blamed on Muslim fighters have left about 2,200 people dead and many injured, including Muslims
Two other officers suffered serious injuries, while three reporters and 13 passers-by suffered minor injuries, he added.
Meanwhile in the capital, Bangkok, 780km north of Yala, a state anti-corruption body announced that it would freeze an additional $63m in assets believed to be controlled by Thaksin Shinawatra, the former prime minister who has been accused of corruption.
The latest order to freeze the assets of Thaksin and his family would bring to more than $2.1bn the sum frozen on suspicion that it was obtained through corrupt means, said Sak Korseangruang, spokesman for the state Assets Examination Commission.
It was previously reported that more than $2.5bn in assets had been frozen, but Sak explained that some money had been counted twice because of confusion over money sought and money actually found.
The assets frozen Monday are in bank accounts, mutual funds and other financial instruments mostly under the name of Thaksin's wife Pojamarn.
Since the middle of last month, the commission established after a September coup that deposed Thaksin has been freezing assets belonging to him and his family pending the outcome of court cases related to charges of corruption and abuse of power.
If the courts rule against Thaksin, the money could be seized by the government.
Thaksin has denied any wrongdoing and accused the military-appointed government that succeeded him of persecuting him for political reasons.
Thaksin became a billionaire in the telecommunications sector before entering politics and serving as prime minister between 2001 and 2006.