Violence in the deep South has escalated after it was agreed at this week's peace talks safety zones would be set up in the area.
Local people are concerned some insurgents may object to an umbrella insurgency group's recent agreement to set up safety zones with the government in southern border provinces.
But Deputy PM Gen Prawit Wongsuwon is not totally convinced, saying on Friday the atrocities might have been caused by personal rifts or had nothing to do with the peace talks.
"I don't think they are related [to the peace talks] but we're investigating," he said.
The latest round of killings started when the Mara Pattani group had peace talks with government negotiators in Kuala Lumpur on Tuesday and agreed five districts of Narathiwat, Pattani and Yala provinces should become safety zones.
Three incidents happened in Narathiwat and Pattani provinces on Thursday alone, claiming eight lives.
The latest incident involved three non-commissioned soldiers gunned down at a flea market in Ban Tabae of tambon La-nga in Mayo district of Pattani at about 7.30pm.
The dead were identified as Sgt Ahamad Sama-ali, 32 of Pattani's Sai Buri district, Pvt Thanakorn Khimthongdonkhu of Phangnga province, and Pvt Narongsak Mamui, 23 of Nakhon Si Thammarat province. A local resident was injured by a stray bullet.
Witnesses said about eight gunmen pretending to be customers at the market shot the soldiers at close range.
Less than two hours earlier, security guard Kasem Toyo from Yala province was shot dead in Ban Buketkong village of tambon Lubo Yirai in the same district.
In the morning, an assistant village head, his eight-year-old son and three relatives died as their pickup truck was ambushed in tambon Khok Lator of Rueso district, Narathiwat.
The pickup truck was carrying the 47-year-old village head, his 39-year-old wife, and his 42-year-old sister-in-law, as well as another young son and a niece who were on their way to school.
Security authorities said insurgents recently adopted a two-team tactic -- one pinpoints a target for the other to shoot.
In the case of the assistant village head's family, a team of gunmen ambushed the pickup truck and another team about 40 metres away reached the vehicle that plunged into a roadside and killed victims point-blank.
Rueso police chief Pol Col Ruangsak Buadaeng said on Friday an insurgent group of Amdan Maeroh might be responsible for the murder.
The group was active in Rueso and Sri Sakhon districts of Narathiwat and Raman district of Yala that were adjacent and its members were wanted for long records of violent attacks, he said.
On Tuesday, the day of the peace negotiation, a bomb-rigged pickup truck was found near a border patrol police base in Songkhla's Thepha district.
The truck was taken away from a couple aged 51 and 41 who were Thepha natives and whose bludgeoned bodies were found in the Thepha River on Wednesday.
The safety zone agreement is what local people need but the subsequent killings showed some groups of insurgency might oppose it, said Nimu Makajay, an Islamic leader in Yala.
About 1,000 people and government officials in Narathiwat's Rueso district marched Friday morning to condemn the violence. They included pupils who were friends of the young attacked in Rueso Thursday morning.
