Citing deteriorating security and a mounting toll on Wednesday, the Thai cabinet approved a three-year special defence budget of $66.3 million for the weaponry, a classified cabinet document said.
"The arms procurement project for the defence ministry is classified as a top priority aimed at boosting security officers' maximum efficiency" in the southern provinces of Yala, Pattani and Narathiwat, said the document, a copy of which was obtained by news agency AFP.
"The situation in the three southern provinces is deteriorating (into) both urban and rural guerrilla warfare, and it is obstructing the government's development plan as well as the establishment of security," it said.
Six procurement projects were approved, including one allowing the Defence Ministry to acquire seven attack helicopters from the US and pay $7.1 million for their repair, upgrade and transport.
The projects also allow the purchase of 24,439 assault rifles and machine guns to replace obsolete weaponry used by some of the security forces in southern Thailand, the document said.
Separatist struggle growing
Violence has escalated sharply following the suffocation and crushing to death of 78 demonstrators in police custody in October 2004.
More than 800 people have been killed and 1200 wounded since the start of the unrest in January 2004.
The authorities and analysts have blamed the violence on organised crime, Islamist separatists, smugglers as well as corrupt police, soldiers and politicians.
No one has claimed responsibility for the killings, and the government has not blamed a specific group for the attacks.
Paramilitary officers inspect cars
after a blast in Narathiwat in June
In the latest violence, three people were shot dead in Narathiwat and Pattani provinces, including a Buddhist school principal.
Chaiyant Chaikweang became the 25th teacher to be shot and killed since the violence erupted last year. And a 30-year-old trader, Niyom Sakdaukosakul, was shot and killed in Yarang district of Pattani.
A village defence volunteer Pibul Sirirat, 52, was also shot eight times in Yarang and died on Tuesday.