Suspected insurgents killed at least 15 volunteer village defense officers and wounded four others in Thailand's Muslim-majority south, police said Wednesday.

The late-night attack targeted a security checkpoint in southern Yala province. An unknown number of assailants then used explosives and scattered nails on roads to slow down a response from security forces.

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

"This is one of the biggest attack[s] in recent times," he said.

Thailand's three most southern provinces of Pattani, Narathiwat and Yala have faced a Malay-Muslim separatist insurgency since 2004 that has claimed nearly 7,000 lives.

Government symbols and representatives are often the target of attacks.

Yala, Pattani and Narathiwat were part of an independent Malay-Muslim sultanate before predominately Buddhist Thailand annexed them in 1909.

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cw/se (dpa, Reuters, AP)