Security staff stand in guard after an assault took place in Yala province in southern Thailand, Nov. 5, 2019. (Photo: Xinhua)

BANGKOK, Nov. 9 (Xinhua) -- The Thai Army told the Thai media on Saturday that seven suspected rebels involved in a massacre killing had been arrested.

They were arrested on Friday night in the deep south and a covert operation was jointly conducted by the Thai military and police.

Deputy Prime Minister Gen Prawit Wongsuwan said last Tuesday's vicious assault, in which 15 village defense volunteers were murdered in Yala Province, was the deadliest attack in the years-long insurgency.

"We have netted all together 7 suspects. One was quickly arrested following Tuesday's attack," said Col Pramote Prom-in, spokesman of the Internal Security Operations Command (Isoc)'s Region 4 Forward Command. "We netted another 6 on Friday night in Pattani and Yala Provinces."

Col Pramote said he suspected that 30 to 40 people were involved in the attack, and it remained unclear which separatist group is responsible for the deadly attack.

No group has stepped forward to claim responsibility for the attack yet.

Meanwhile, Thai Prime Minister Prayut Chan-o-cha, who is also the defense minister, has reiterated that he will not tolerate terrorism acts on the Thai soil.

All those involved and arrested will have to face the full force of the Thai law, said Prayut.