Police said on Friday a village chief was shot dead in his car and a fireman died in hospital after being shot while trying to put out a blaze at one of the burning buildings in the southern province of Narathiwat that borders Malaysia.
The night violence was the worst in three months of unrest that started on 4 January when gunmen burst into an army camp, stealing nearly 400 guns and killing four soldiers, and 20 schools in Narathiwat were burned.
At least 60 people, including three Buddhist monks, have died in the violence, which has rekindled fears of a separatist rebellion in the impoverished region where few people have
strong emotional ties to the distant capital, Bangkok.
Police said troublemakers intent on reviving a low-key insurgency that racked the region in the 1970s and 1980s were targeting disaffected and unemployed Muslim youngsters.
At least 10 suspects, most aged under 18, were arrested after the violence and were now in military custody, police said.
"I've ordered urine tests on these teenagers who are believed to be drug addicts used by masterminds intent on stirring unrest," Lieutenant General Prung Bunpadung, commander of the southern police, told Reuters.
The south of the country has
experienced increased violence
Lieutenant General Chalermdej Jombunud, commander of the Special Branch Police, said youths arrested previously had been hired by drug trafficking or smuggling gangs, and had received no overseas military training.
"We've arrested 20 of them in the past, mostly teenagers who confessed that they were paid 1500 baht ($38) to set fire to schools and other public places. These people aren't ideological. They did it because they were unemployed."
Although Thailand says the problem appears to be internal, independent analysts say international groups, such as Usama bin Ladin's al-Qaida network, might find fertile minds among the region's disaffected youth.
The government has tightened security at an airport in the southern commercial centre of Hat Yai amid fears the violence in the three southernmost provinces could escalate.
Prime Minister Thaksin Shinawatra told reporters during a trip to north-eastern provinces the culprits would face severe penalties.
Thaksin, who is due to travel to the south next week to bolster a tarnished political image, said the unrest had intensified because police were closing in on the masterminds of the initial raid on the army camp.
However, authorities have neither retrieved the weapons stolen in January nor arrested a single suspected ringleader.