Yingluck Shinawatra
Thailand's Prime Minister Yingluck Shinawatra speaks during a new conference at the Government House in Bangkok in January, 2013 REUTERS

Thailand government forces thwarted an early-Wednesday attack by militants dressed as soldiers on a military base in the violence-hit southern region of the country, killing 19 insurgents in the shootout, authorities said.

The militant raid, in Narathiwat province near the border with Malaysia, was carried out by some 50 insurgents wearing military-style uniforms. The attack was one of the biggest in recent years and is believed to be one of the most fatal tolls the insurgents have suffered in nine years of insurgency in the Muslim-dominated provinces of Thailand’s south, the Associated Press reported, citing Thai authorities.

The assailants opened fire at the military base in Bacho at around 1:30 a.m. Wednesday morning, Lt. Gen. Paradorn Pattanathabutr, secretary-general of the National Security Council of Thailand, told Reuters.

Violence flared in the south in recent weeks, with militants killing five soldiers in two ambushes in Yala province on Sunday and targeting civilians from other parts of Thailand in recent weeks, according to a report in the Wall Street Journal.

The army has declared a curfew for the area within 5 kilometers (3 miles) of the base for Wednesday night into Thursday, Regional army commander Lt. Gen. Udomchai Thammasaroraj said in an interview on ThaiPBS channel, as reported by the AP.

Thailand's three Muslim-majority southernmost provinces -- Yala, Narathiwat and Pattani -- have been beset by separatist unrest in recent years.

The three southern provinces were annexed to what was formerly known as Siam more than a century ago. The residents of these provinces, most of them Muslims (unlike the rest of Buddhist-dominated Thailand), have long complained of discrimination by the central government.

Though the insurgency is seen largely as a movement for autonomy, the militants have remained silent about their goals.

More than 5,000 people have been killed since the violence erupted in 2004 after decades of hostility against the government.

The Thai government has deployed tens of thousands of troops and police to the region, but it has not been able to contain the violence.