This is the moment suspected terrorists threw pipe bombs at a police checkpoint in the restive southern Thailand.

CCTV footage shows several insurgents hurling the improvised explosives at a pickup truck, shortly before the blast at the Batu checkpoint in Narathiwat province on August 11 evening.

Authorities said one pipe bomb landed inside and damaged a building, while another was thrown inside a tent on the side of the road.

A volunteer ranger, Pitakchai Phueng-in, assigned to the 11th Marine Corps Ranger Company, suffered minor injuries.

Police said they have cordoned off the scene for investigation.

Islamic separatist terror attacks target the three southernmost provinces of Thailand - Yala, Pattani and Narathiwat - next to the border with Mulsim neighbors Malaysia. Thai state employees and infrastructure are often hit while attacks on civilians are rare.

Officials believe the conflict dates to a deal in 1909 that the British Empire struck to incorporate the Muslim region into the Siamese mainland.

The region's culture is more similar to Malaysia and dramatically different to Buddhist Thais causing decades of tension that lead to the emergence of separatist groups fighting for independence in the 1960s.

The struggle has continued ever since with more than 7,344 people killed and 13,641 injured between January 2004 and March 2022.

The British Foreign & Commonwealth Office warns against all but essential travel to the region while Canada's government warns its nationals to 'avoid all travel' to the three provinces.