The army has reached a breakthrough pact with the separatist supporters Mara Patani to create a "safety zone" in the deep South, the lead negotiator said on Wednesday
Whether such zones can actually be safe is questionable, since Mara Patani is based in Malaysia, and none of the groups on the ground has participated in talks.
Mara Patani officials were not immediately available for comment.
The government has been negotiating with Mara Pattani, a self-styled umbrella group that claims to speak for the insurgents but is based in Kuala Lumpur and consists of older separatists.
"Both sides have agreed to the creation of a safety zone in one of the three southern provinces to show their good faith," negotiator Maj Gen Sithi Trakulwong said Wednesday.
"This is the most progress we've made in over two years of negotiations."
Maj Gen Sithi said the agreement would be finalised next week in Malaysia, which has facilitated the discussions. Mara Patani members do not travel to Thailand.
The safety zones would be an area where fighting is off-limits, but precise details of its location or size have not been made clear.
Talks between the government and the insurgents began in 2013 under former prime minister Yingluck Shinawatra, but stalled quickly and were not immediately resumed after the military overthrew her government in May, 2014.
The insurgent group Barisan Revolusi Nasional (BRN), which has been left out of negotiations, is now the main actor in the three provinces, they say.
"Any agreement on the implementation of safety zones that does not include the military wing of BRN will very likely result in an escalation of violence", said Anthony Davis, a Bangkok-based security analyst with IHS-Jane's and Bangkok Post contributor.
Mara Pattani has said in negotiations with the Thai government that it was not responsible for any attacks or violence, leaving open the question of how it can conduct peace talks if it cannot control events in the deep South.