NARATHIWAT, THAILAND - Separatist militants in Thailand's Muslim-majority south have shot dead four civilians including two female Buddhist teachers, one of whom was pregnant, police said Wednesday.

The violence erupted a day before the country?s education minister was due to visit the troubled region, where more than 3,600 people have been killed during a five-year insurgency.

Gunmen disguised as soldiers ambushed a vehicle carrying teachers in Narathiwat province late Tuesday, stopping them with a fake warning that a bomb was being defused on the road ahead before opening fire, police said.

The attack killed one teacher instantly while a colleague who was eight months pregnant died on the way to hospital, police said. Two other teachers and the driver were wounded.

Also in Narathiwat, a Muslim man was shot and killed in a late night attack at a local teashop and a Buddhist scrap dealer died in a separate drive-by shooting.

Schools and teachers are frequent targets of attacks in the Muslim-majority south because militants see the education system as an effort by Bangkok to impose Buddhist Thai culture on the mainly ethnic Malay region.

The insurgency in southern Thailand erupted in January 2004 and attacks have become increasingly brutal. Buddhist-majority Thailand annexed the area in 1902, sparking decades of tension.