(Adds Industry Minister quote, updates share price)

By Robin Paxton

MOSCOW, July 24 (Reuters) - An attack on Mechel's (MTL.N: Quote, Profile, Research) pricing policy by Russian Prime Minister Vladimir Putin erased almost one third of the miner's market value on Thursday as investors fled on fears it could fall victim to a state campaign. Putin accused Mechel, Russia's largest coking coal miner, of selling its raw materials domestically at double the price of its exports and threatened punitive action against the firm owned by Russia's joint 12th-richest man, Igor Zyuzin.

"We are fielding calls from clients who are losing a million dollars a second," said a Moscow-based analyst with an investment bank, who declined to be named.

New York-listed Mechel, also Russia's sixth-largest steel maker, declined immediate comment.

"I'm asking the federal anti-monopoly service to pay special attention to this problem. And maybe even the investigative committee of the Prosecutor General's office," Putin told steel company owners at a meeting to discuss market developments.

"In the first quarter of this year, the company sold its raw materials abroad at half the price of its domestic prices."

Zyuzin, Mechel's billionaire majority owner, did not attend the meeting in the city of Nizhny Novgorod east of Moscow.

Mechel's pricing is already subject to an investigation by Russian anti-monopoly authorities and any decline in investor confidence threatens to derail a preferred share placement planned by the company for August.