Bangkok -

Anti-narcotics police seized 2.2 million methamphetamine pills and 50 kilograms of crystal meth in northern Thailand, and arrested three alleged traffickers, police said on Friday.

“If they had sold these drugs, they would have made not less than 1 billion baht (33.3 million dollars),” Narcotics Suppression Bureau Commissioner Lieutenant-General Chaiwat Chotima told The Manager online news service.

Acting on a tip-off, police set up check points on the highway at Chiang Saen, Chiang Rai province, 630 kilometres north of Bangkok.

At 9.30pm on Thursday (14.30 GMT) a pickup truck refused to stop at the checkpoints and police gave chase, and stopped it by shooting out one of the tyres.

The three suspected traffickers attempted to flee but after a brief exchange of fire, they were arrested, Chaiwat said.

The Shan State in north-east Myanmar, which borders Chiang Rai province, is believed to be the main source of methamphetamines and crystal meth in South-East Asia.

In 2011, Thai authorities seized more than 49 million methamphetamine pills and 1 232 kilograms of ice. - Sapa-dpa