Suspected insurgents detonated a motorcycle bomb in southern Thailand on Saturday, killing two military rangers and wounding 11 people, the second serious attack in as many days after one of the Muslim rebel groups operating in the area agreed to hold peace talks.
The blast on a road in Yala province, in which two civilians were among the wounded, followed a similar motorcycle bombing in neighbouring Narathiwat province on Friday that wounded six people.
The attacks come two days after a landmark agreement between the Thai government and the Barisan Revolusi Nasional (BRN) rebel group to start talks aimed at ending a conflict that has claimed more than 5,000 lives since 2004.
The agreement, brokered by Malaysia, was signed in Kuala Lumpur and the two sides are expected to begin preliminary talks in two weeks.
Various shadowy rebel groups are active in the southern provinces bordering Malaysia and successive Thai governments and the military have made contact with some of the groups and are believed to have held secret talks, but have never had open discussions.
Analysts said it was far from clear whether all rebel groups supported peace talks with the Thai government.
"Attacks in the aftermath of the signing of the peace dialogues fit in with the pattern of radical elements who oppose holding talks with Thai authorities and who know that the agreement took place within the Thai constitution and that there will be no autonomy for the southern states," Sunai Phasuk of Human Rights Watch told Reuters.
An escalation in attacks by rebel groups in the coming weeks would be a test of Thailand's commitment to holding peace talks with the BRN, he said.
The provinces of Pattani, Yala and Narathiwat were once part of a Malay sultanate before being annexed by Thailand in 1909 and resistance to Buddhist rule from Bangkok has existed for decades in the predominantly Muslim provinces.
The conflict waned briefly in the 1990s before resurfacing violently in 2004. Since then, 5,300 people have been killed according to Deep South Watch, which monitors the violence.