(Reuters) - Mark Karpeles, the chief executive of Mt. Gox, said he would not come to the United States to answer questions about the Japanese bitcoin exchange's U.S. bankruptcy case, Mt. Gox lawyers told a federal judge on Monday.

In the court filing, Mt. Gox lawyers cited a subpoena from the U.S. Department of Treasury's Financial Crimes Enforcement Network, which has closely monitored virtual currencies like bitcoin.

"Mr. Karpeles is now in the process of obtaining counsel to represent him with respect to the FinCEN Subpoena. Until such time as counsel is retained and has an opportunity to 'get up to speed' and advise Mr. Karpeles, he is not willing to travel to the U.S.", the filing said.

The subpoena requires Karpeles to appear and provide testimony in Washington, D.C., on Friday.

The court papers also said a Japanese court had been informed of the issue and that a hearing was scheduled on Tuesday in Japan.

Bitcoin is a digital currency that, unlike conventional money, is bought and sold on a peer-to-peer network independent of central control. Its value has soared in the last year, and the total worth of bit coins minted is now about $7 billion.

Mt. Gox, once the world's biggest bitcoin exchange, filed for bankruptcy protection in Japan last month, saying it may have lost nearly half a billion dollars worth of the virtual coins due to hacking into its computer system.

According to Monday's court filings, the subpoena did not specify topics for discussion.

In the court filings, Karpelès' lawyers asked the court to delay the bankruptcy deposition to May 5, 2014 but said that Mt. Gox could not guarantee that Karpeles would attend that either.

The case was in Re: Mt Gox Co Ltd in the U.S. bankruptcy court for the northern district of Texas, Dallas division, No. 14-31229-sgj15.

(The story corrects headline and first paragraph to show the Karpeles is the chief executive of Mt. Gox, not the founder.)

(Reporting by Devika Krishna Kumar in Bangalore; Editing by; Eric Walsh)