BANGKOK: Suspected separatist insurgents killed at least 15 and wounded four village defense volunteers in a late-night shooting at a security checkpoint in Thailand’s Muslim-majority south, security officials said on Wednesday.

The attackers in southern Yala province also used explosives and scattered nails on roads to delay pursuers late on Tuesday night in what authorities described as the biggest gun attack in years.

“This is likely the work of the insurgents,” Colonel Pramote Prom-in, a regional security spokesman, told Reuters.

A decade-old separatist insurgency in predominantly Buddhist Thailand’s largely ethnic Malay-Muslim provinces of Yala, Pattani, and Narathiwat has killed nearly 7,000 people since 2004, according to Deep South Watch, which monitors the violence.

There was no claim of responsibility, as is common with attacks in Thailand’s deep south.

Some rebel groups in the south have said they are fighting to establish an independent state.