BANGKOK • At least 60 people, among them children, were injured when two bombs went off one after the other at a major supermarket in Thailand's restive south yesterday afternoon.

Of the 60 who were hurt, 21 suffered serious injuries, reported Reuters.

The authorities suspected that Muslim militants, fighting for a separate state in the deep south of the predominantly Buddhist country, were behind the attack outside Big C supermarket in Pattani.

Police said the first device was packed inside a motorcycle in a carpark, while the second was a car bomb. A video posted by a witness on Twitter showed the second bomb detonating in a large fireball, sending bystanders running for cover.

The blast destroyed the front of the supermarket, scattering debris over a wide area and sending up a column of black smoke.

"I heard a very loud explosion," a resident who lives close to the supermarket told Agence France- Presse, requesting anonymity.

"Minutes after that, I heard the sirens of rescue cars and ambulances. I feel bad about it... it happened at a place where people go to buy things."

It is not the first time that the Pattani branch of Big C, Thailand's second-largest hypermarket operator and the only supermarket chain to operate in the southern border provinces of Pattani, Yala and Narathiwat, has been targeted. An improvised explosive device triggered by a mobile phone went off in its carpark in 2005, while its premises were torched in 2012.

Defence Ministry spokesman Kongcheep Tantrawanit said the government condemned the bomb attack and considered it a grave violation of human rights.

Southern Thailand has been rocked by near-daily shootings and bomb attacks for more than a decade as ethnic Malay rebels battle Thai troops in their quest for more autonomy from Bangkok. The fighting has claimed more than 6,500 lives since 2004, according to independent monitoring group Deep South Watch. It said that last month alone, there were 109 incidents and 21 deaths.

The separatist movement, founded on ethnicity and religion, has become increasingly violent since 2001.

Talks between the Thai junta and Mara Patani, an umbrella group claiming to represent the militants, began in 2015 but these have staggered along without any result. Barisan Revolusi Nasional, one of the insurgent groups, rejected Bangkok's peace plan last month and called for international observers and a neutral mediator to facilitate the talks.

But shortly before yesterday's attack, junta chief Prayut Chan-o-cha reiterated his opposition to foreign involvement in solving the festering conflict. "We must keep this issue away from the reach of the international arena," he told reporters in Bangkok.