Suspected separatist Muslim fighters have killed five police officers and later stole their weapons in an attack in south of Thailand, police say.

About five to six fighters followed a pickup truck carrying the undercover policemen and attacked them on a road in Thung Yangdaeng district in Pattani province, Police Colonel Kowit Rattanachote said on Wednesday.

He said the police pulled over their car and attempted to take cover after the armed men started firing into their vehicle.

The bodies of four policemen were found next to the vehicle and another was found inside.

The officers belonged to a regional police squad that cracks down on oil smuggling.

The fighters suspected to be members of the Barisan Revolusi Nasional (BRN) group searched the police's vehicle and took away their weapons before fleeing in a pickup truck, police officer said. 

Wednesday's attack follows an explosion at a school in Yala province the previous day that killed two soldiers and wounded a child.

'Planned ambush'

Al Jazeera's Veronica Pedrosa reporting from Thailand capital Bangkok said the attack seemed to be a planned ambush.

"The police were on a mission to seize petrol gasoline that is smuggled on regular basis.The question that people are asking is how the militants knew about the operation.

"The problem about the peace process between the government and the rebels is that the violence continues along with the progress, she added.

The government entered a peace process with the BRN rebel group this year and the talks will resume next month.

More than 5,000 people have been killed in predominantly Buddhist Thailand's three Muslim-dominated southernmost provinces since an Islamic insurgency erupted in 2004.

Source: Aljazeera And Agencies