BANGKOK, Dec. 8 (Xinhua) -- Seven suspected drug traffickers were killed in a clash with Thai army rangers in northern Thailand on Thursday, police said.

A group of suspected drug traffickers had been spotted in a mountainous area in Mae Aye district of Chiang Mai province, which borders Myanmar, by the patroling rangers of Phamuang Task Force.

Seven of the unidentified suspects were killed in the 15-minute clash with the rangers while others escaped into the mountainous area.

The rangers seized an estimated 400,000 methamphetamine pills and more than 10 kilograms of heroin, contained in bags and left behind by the suspected traffickers, the police said.