NARATHIWAT, Thailand (AFP) - In one of the most deadly attacks in Thailand's long-running insurgency, scores of heavily-armed gunmen stormed a southern army base Wednesday, authorities said, leaving 16 militants dead. In the unusually brazen early-morning assault, 100 militants, dressed in army fatigues and armed with AK47 and M16 assault rifles, attacked the unit in Narathiwat province, unit commander Captain Somkiat Pholprayoon said. "Sixteen militants were confirmed dead after the attack," he told reporters at the scene, adding that the military and police were in "hot pursuit" of the 60 to 70 militants who fled the base after the attack.

The government expressed sorrow over the deaths, one of the highest single death tolls in some eight years of violence in Thailand's deep south, but praised the military operation, saying the army had had no choice.

"The government has no policy of using violence to deal with southern unrest but in this incident (militants) attacked the military base," Deputy Prime Minister Chalerm Yubamrung told reporters in Bangkok.

A shadowy insurgency has been fighting for greater autonomy for the country's southernmost provinces since 2004, with shootings and bombings occurring on a near-daily basis.

More than 5,500 people have been killed, both Buddhist and Muslim, in the bloody conflict.

Chalerm, who heads the government's special body in charge of the southern unrest, recently proposed imposing a curfew in certain areas of the most affected provinces.

"If we impose a curfew then militants will find it more difficult to enter the area," he said Wednesday.

Religious leaders oppose the move, saying it will do nothing to solve the underlying problems. The Thai cabinet is set to discuss the proposal Friday.

Critics accuse the government of failing to address the grievances of Thailand's Malay Muslim minority, including alleged abuses by the military and a perceived lack of respect for their ethnic identity, language and religion.

Members of Thailand's security forces are frequently targeted in ambushes and roadside bombs, but organised attacks on military bases are relatively rare.

No military casualties were reported in the early hours assault at the base in the Bacho district of Narathiwat province, one of three Muslim-dominated provinces near the border with Malaysia. An army spokesman had earlier put the militants' death toll at 17.

"We learned of the attack in advance from defected militants," Colonel Pramote Promin, southern army spokesman told Thai television.

He added that a key local leader of the fighters, who wore bulletproof vests during the attack, had been killed in the clashes.

Southern army commander Lieutenant General Udomchai Thammasarorat called for local villagers to stay in their homes for 24-hours, for their "safety and to prevent any confusion during the pursuit of militants", he told broadcaster Thai PBS.

A report by the International Crisis Group on the violence in December said insurgents had grown "bolder and stronger" amid political inaction from successive Bangkok governments.

The attack Wednesday is "part of a trend" towards bigger, bolder attacks by militants showing a new "willingness on the part of militants to engage the security forces head on," said Matthew Wheeler, an ICG South East Asia Analyst.

"The fact that so many militants were killed is very unusual," he said, adding the last time there was such a high death toll was in April, 2004.

The ICG report recommended a greater push towards decentralisation and closer engagement with local civil society groups and peace negotiations with insurgents.

It added that the deployment of 60,000 security forces and an emergency decree "have not achieved any appreciable decline in casualties".