Suspected Muslim insurgents attacked police and a government office in Thailand's deep south on Tuesday, killing one official as they seized hostages, police said.

More than a dozen armed men dressed in black seized 13 civil servants in a local government office in Narathiwat province, police investigator Wongduan Kamsri told Reuters. The head of the office was shot three times in the head and the surviving hostages fled, Wongduan added.

No one immediately claimed responsibility for the attacks. But Thailand's three southernmost provinces of Pattani, Yala and Narathiwat, all majority Muslim, have been plagued by unrest since 2004, when a long dormant separatist rebellion resurfaced.

As police traveled to the scene of Tuesday's attack, gunmen opened fire on one vehicle and tried to detonate a bomb planted in the road as another car passed over it, Wongduan said, adding that no officers were injured.

"This incident was well planned and coordinated by the insurgents," said Pramote Prom-in, a spokesman for the military-run Internal Security Operations Command.

The region abutting the Malaysian border was an independent Malay Muslim sultanate a century ago before being annexed by Thailand, an otherwise predominantly Buddhist state.

More than 6,500 people have been killed since 2004 in the sporadic violence.

Shortly after taking power in a 2014 coup, Thailand's ruling junta vowed to bring peace to the deep south within a year and the country's defense minister expressed optimism the violence could be halted.

"From what we've done so far, I believe the unrest might end in 2016," Prawit Wongsuwan said on Wednesday during the military government's year-end review.