BANGKOK - Two Buddhist monks were killed and two soldiers seriously wounded in a roadside bomb explosion in southern Thailand early Monday, police said.

The attack occured around 6 am local time when six soldiers were taking two monks to collect alms in Yaha district, Yala province, the Thai News Agency (TNA) quoted police as saying.

The two monks died at the scene, and two injured soldiers were rushed to Somdej Phra Yupparaj hospital for treatment, TNA said.

Police said the bomb was a homemade explosive device built into a cooking gas cylinder hidden on the roadside.

The bomb was attached to an electric detonation wire over 100 metres long extending into the nearby roadside forest, and that it was triggered manually using a battery.

Police blamed separatist militants for the attack.

More than 4,000 have been killed by suspected separatists since January 2004 in three southernmost provinces of Yala, Pattani, Narathiwat, and some parts of Songkla province.