Bunhoam Chanthai, 30, an Irrigation Department employee, was riding with his three-year-old son and eight-year-old daughter when a man on another motorcycle opened fire on them, said Colonel Wichai Inthawong, superintendent of Yarang Police Station.

Caretaker Agriculture Minister Sudarat Keyuraphan said she had yet to receive reports of the incident but expressed her condolences to the victims' family.

Irrigation officials have complained about a government policy that makes them return government-issued firearms to the authorities for fear that they will be targeted by insurgents.

"We end up having to use our own money to buy weapons," said an officer who refused to be identified.

About 15 irrigation officials in the three southernmost provinces have been killed since January 2004, said the officer, adding that the ministry had initiated no new measures to improve staff security.

In another attack, village defence volunteer Roning Yusof, 57, survived an onslaught with an M16 automatic rifle.

Police said militants were targeting more village defence volunteers who worked or spied for the state.

In Nakhon Si Thammarat, members of the provincial Islamic committee expressed contempt for the authorities for conducting an unauthorised search of their mosque on Wednesday.

The investigation, conducted without a court warrant, followed a false tip-off that the basement in the place of worship was used to hide weapons for rebels in the three southernmost provinces, Kariya Kijarak, the vice chairman of the Central Islamic Committee of Thailand, said following a meeting with the provincial chapter.

Kariya suggested that the officers had forced their way into the mosque without producing any court document authorising them to enter. It was not clear why the mosque caretaker had not asked to see a warrant.