Eight drug traffickers were shot dead by Thai border forces Monday morning in northern Chiang Rai Province, a senior army officer said.

More than 50 soldiers and police ambushed about a dozen armed drug traffickers trying to enter Thailand through forest at about 5:30 a.m., said Major General Somsak Nilbanjerdkul, head of border troops in Chang Rai.

Somsak said Thai authorities were tipped about the traffickers. He did not say where they were from.

The troops waited for daylight and reinforcement to search the area. They found eight bodies and bags containing 550,000 methamphetamine pills and 70 kg of crystal methamphetamine, he said.

They also found three rifles, a handgun and a pistol. Trails of blood were seen at the scene leading to a "neighboring country".

Thai forces had no casualties, Somsak said.