Thailand's army has declared a curfew in two districts of the country's Muslim-majority south following increased violence in the area.

An army spokesman says the curfew will be in place for eight hours beginning at eight in the evening local time in the districts of Yala and Banang Sata, both in Yala province.

On Wednesday, 11 people were wounded in a bomb attack outside a mosque in Yala, in what police officials described as an attempt to pit Muslims against Buddhists.

Earlier in the day, suspected Muslim insurgents shot and killed eight people traveling in a commuter van. All of the dead passengers were Buddhist.

Yala is one of three southern Thai provinces caught up in a Muslim separatist insurgency that has killed 2,000 people over the past three years.

Thai authorities have increased security throughout the region this week for the anniversary of the 1963 founding of an area separatist group, the Barisan Revolusi Nasional. Police are concerned militants could mark the anniversary with violence.

Some information for this report was provided by AFP and AP.