Thirteen people including five journalists were injured in two separate bomb explosions on a road in Rangae district of Narathiwat on Saturday.
The first blast occurred at 11.11am when six army rangers were patrolling along a local road at Ban Kulupaleh in tambon Tanyongmas.
All were wounded by bomb shrapnel and taken to Rangae hospital where three are in critical condition, said Pol Col Jiradej Phrasawang, chief of Rangae police station.
The wounded rangers are Staff Sgt Wichai Ramchuay and Rangers Wayukhun Chitti-arom, Mongkol Deejai, Suradej Chamkate, Asman Jeh-ahmah and Manuwa Waji.
Pol Col Jiradej said that while police forensic and bomb disposal units were inspecting the scene, the second bomb, suspended from a tree branch about 100 metres away, was detonated about noon, injuring two policemen and five reporters.
The journalists who had rushed to the scene were standing at a distance from the original bomb site when the second device exploded, said AFP photographer Madaree Tohala who was injured.
"We were chatting on the side of the road while we waited for authorities to do their jobs," said Mr Madaree, who was treated for shrapnel in the back and ear.
"I don't know how it happened, I heard a big explosion which was not far from where I was standing and when I opened my eyes I saw my reporter friends lying on the street."
In addition to Mr Madaree, the injured were identified as Pol Sen Sgt Maj Preecha Thongsrimai; Pol Sgt Wittaya Plodlek; Channel 7 reporter Kreeya Tohtanee, Siam Rath reporter Muranee Mama, Channel 5 reporter Santhiti Korjitmate, and Thai PBS reporter Pathitta Noosanthad.
All were taken to Rangae hospital and later moved to Narathiwat Ratchanakarin hospital. None of the reporters are thought to have been seriously hurt.
More than 5,700 people have been killed in the country's three southern border provinces since sectarian unrest re-emerged nearly 10 years ago.
Peace talks brokered by Malaysia have proceeded fitfully over the past few months with little progress.
The next round of talks with the Barisan Revolusi Nasional (BRN), was to take place on Sunday but has been postponed indefinitely following multiple bombing, arson and gun attacks earlier this month.