A Thai officer stands beside the burnt down oil tanker at a gas station in Pattani province, southern Thailand, Wednesday. AP
Officials said most of the targeted sites were convenience stores in petrol stations, all located in the provinces of Pattani, Yala and Narathiwat.
A low-level conflict has rumbled in Thailand's southernmost provinces since 2004, killing more than 7,000 people as militants in the Muslim-majority region battle for greater autonomy from the state.
Seven people were slightly injured in the incidents, a statement from the military said, while police said they were gathering CCTV footage and other evidence.
Authorities said the immediate motive for the wave of attacks was still unclear. Militants usually target symbols of the Thai state and its security forces.
The coronavirus pandemic brought a lull in southern clashes between rebels and the military, but a six-day gun battle in October last year killed six people.
The southern region, heavily policed by Thai security forces, is culturally distinct from Buddhist-majority Thailand, which colonised the area bordering Malaysia over a century ago.
Delegations representing the Thai government and Barisan Revolusi Nasional rebels met in Kuala Lumpur in January for their first in-person peace talks in about two years, though no breakthrough was reported.
Since the insurgency reignited in January 2004, more than 7,000 people have been killed and 13,500 others injured in Thailand's far south, according to Deep South Watch, a local think tank.