Vietnamese troops in Cambodia are preparing for a dry season offensive against resistance guerrillas despite Hanoi's promise to withdraw its forces by September, news reports said Saturday.

About 40,000 troops, including Vietnamese troops and soldiers loyal to the Hanoi-installed regime in Phnom Penh, are stationed in the western Cambodian provinces of Battambang and Pusat along the Thai-Cambodian border, the Thai newspaper The Nation quoted Rear Adm. Manas Pinkulbutr as saying.Manas, deputy commander of the Thai task force in the the provinces of Chantaburi and Trat, was quoted as saying the Vietnamese are poised to attack the Khmer Rouge and troops loyal to guerrilla faction leader Son Sann.

Vietnam invaded Cambodia in 1978, driving out the brutal Khmer Rouge regime under which an estimated 1.5 million Cambodians died.