A first batch of explosives planted inside a parked pickup truck ripped through an area of restaurants and shops in a busy area of Yala city, a main commercial hub of Thailand's restive southern provinces, said District Police Chief Col. Kritsada Kaewchandee.

About 20 minutes later, just as onlookers gathered at the blast site, a second car bomb exploded, causing the majority of casualties. Eleven people were killed and 110 wounded by the blasts.

More than 5,000 people have been killed in Thailand's three southernmost provinces Narathiwat, Pattani and Yala since an Islamist insurgency flared in January 2004.

"This is the worst attack in the past few years," said Col. Pramote Promin, Deputy Spokesman of a regional security agency. "The suspected insurgents were targeting people's lives. They (chose) a bustling commercial area, so they wanted to harm people."