The rangers were traveling by pickup truck to their base at Ban Ya Soop in Patae subdistrict to end their patrol duty. As the vehicle arrived at Ban Baro in Yaha district, a sidecar motorcycle parked at the roadside exploded, the blast hitting the military truck as it passed by.
Police said explosives were built into the sidecar motorcycle and were triggered by presumed insurgents.
The rangers wounded in the attack were sent to hospital for treatment.
Police investigators said a second bomb exploded about one kilometre down the road, apparently targeting the responding security team, but no one was hurt.