The attack, explained National Security Council secretary-general Paradorn Pattanathabutr, was not an indication showing that an ongoing peace dialogue with insurgents' representatives was a failure.
"It is customary [generically] during a peace process [with an armed resistance group] for such an incident, and this attack is not deemed a shift in insurgent violence, as government officials are always the prime targets," he added.
He said the attack was possibly carried out by members of the insurgents opposed to the peace dialogue, who wanted to make their intent known.
Deputy governor Issara Thongthawat was travelling with provincial civil defence chief Chaowalit Chairuerk and two officials in a Toyota Camry, which was escorted by a military vehicle. The blast blew the sedan up in the air, said a witness, who said it dropped 50 metres away from the blast site. Yala governor Dejrat Simsiri said he was looking into a suspicion of an inside job, given that the bomb precisely targeted the sedan.