Raids on jungle drug labs have been met with heavy artillery fire, Myanmar narcotics police said Thursday, in an area riddled with armed groups accused of pumping out much of the world's methamphetamine.Myanmar is under increasingly intense pressure from its neighbours to close down the meth labs festooning lawless parts of Shan State, the heart of the notorious "Golden Triangle".A major crackdown kicked off last month in Kutkai township, northern Shan, the army has said, where