A curfew has been declared in two districts of Yala following the brutal massacre of eight passengers on a minibus on Wednesday.

The government also banned the wearing of military style clothing and the use or possession of radio communication gear.

More troops - 20 companies of rangers - would also be sent to the South by the end of the month.

The curfew, announced yesterday by the Fourth Army Region, applies to Yaha and Bannang Sata districts. It will prohibit people from leaving their homes between 8pm and 4am.

The ban, applied under martial law provisions, would come into force immediately, the Army said.

"Those who need to leave their homes during the curfew must ask permission from military units stationed in their areas," it said. "Permission will be issued on a case by case basis."

Yaha and Bannang Sata are regarded by the military as "red zones" where insurgents operate freely with full support from local residents.

It was the first time the Army has enforced a curfew in three years since the escalation of violence in the predominantly Muslim region began in January 2004.

More than 2,000 people have been killed over the past three years, but the situation has got worse this year with more frequent and more brutal attacks by radical militants.

The latest atrocity took place on Wednesday morning when some 10 militants killed eight Buddhists passengers in a commuter van in Yaha in an execution style attack.

The massacre may have prompted a bomb attack on a mosque in Yaha on Wednesday night in which at least 11 people were injured, some of them seriously.

Around 100 Muslims in Baroh sub-district gathered yesterday to block the Yaha-Patae Road in an act of protest. They demanded the authorities to bring the bomber to justice.

Fourth Army Commander Lt General Viroj Buacharoon said the curfew would be imposed in other areas if same scale of violence occurred elsewhere.

The Army also stepped up moves to try to counter the militants, such as banning people from wearing military-style uniforms in Pattani, Yala, Narathiwat, and Songkhla's five districts.

"People shall refrain from wearing clothes similar to military, police, ranger and other kinds of government security forces," the statement said. "Those who refuse to comply will be considered militants and might face legal action in accordance with the martial law."

Military-style uniforms are popular among insurgents as they want local residents to believe that government troops are carrying out the violence against Muslims.

The military have also told local residents to tell local troops if they receive guests or new family members. Everyone must carry an identity card everywhere they go, the Army statement said.

The use or possession of radio communication gear was banned in another announcement. Shops in the three provinces were also ordered to stop selling such equipment. The instruction did not refer to mobile phones, which have been used to detonate bombs. People who violate the order face up to five years' jail or a fine up to Bt100,000, or both.

Prime Minister Surayud Chulanont said the government would boost troop numbers in the South shortly. By the end of the month, 20 companies of rangers would be dispatched. The government needed 3,300 police officers to cover all the danger areas in the region, he said.

Although the violence was still continuing, Surayud said many security measures in the restive south had been improved since he took power nearly six months ago.