* Sberbank move follows VTB lawsuit against Mechel
* VTB says it will drop lawsuit if payment agreement reached
* Kremlin aide said compromise was closer than ever (Adds detail, updates shares)
By Svetlana Burmistrova and Alexander Winning
MOSCOW, Oct 1 (Reuters) - State-run Russian lender Sberbank filed a lawsuit against debt-laden Mechel on Wednesday, erasing earlier gains in the coal and steel producer's shares.
The bank is the second creditor to take legal action against Mechel after months of talks on ways to help the loss-making miner to pay off at least some of its $8.6 billion in debt.
The database of a Moscow court showed the filing had been lodged but did not disclose further details. The Itar-Tass news agency said the lawsuit demanded the repayment of 1.5 billion roubles ($38 million), citing an unnamed source.
Sberbank declined to comment and Mechel said it had yet to receive notice of the lawsuit.
Shares in Mechel were up 1.9 percent at the market close in Moscow, having lost most of an earlier 18 percent gain when another major lender, VTB Bank, said it would drop its lawsuit against Mechel if a debt agreement could be reached.
"We have failed to agree so far; (if we) agree we will withdraw our lawsuits from the court," Andrei Kostin, the head of VTB, told reporters on the sidelines of a VTB Capital conference in Moscow. VTB filed its 3 billion rouble lawsuit against Mechel last week.
Russian officials have been looking at ways of helping Mechel, controlled by businessman Igor Zyuzin, for months and have proposed several schemes, including a plan to convert part of the company's debt into shares.
A senior Kremlin aide, Andrei Belousov, said on Monday that Mechel was closer than ever to reaching a compromise with creditors, though news agency Interfax reported on Wednesday that Mechel's other major creditor, Gazprombank, has not ruled out legal action in future. (1 US dollar = 39.6440 Russian rouble) (Writing by Vladimir Soldatkin and Polina Devitt; Editing by Elizabeth Piper and David Goodman)