The disappearance of the Mt. Gox website content on Tuesday marked another setback for efforts to gain legitimacy for the Bitcoin virtual currency. The URL of the exchange was returning a blank page, following Sunday's resignation of CEO Mark Karpeles from the Board of the Bitcoin Foundation.

A report spread online and believed to be an internal Mt. Gox document said more than 740,000 bitcoins were missing from the exchange. It said the theft went unnoticed for several years and turned on disguised withdrawals.

A theft of that magnitude would equate to losses of $350 million (255 million euros) at current Bitcoin prices, the report suggested.

Many open questions

Tokyo investors in the frontier electronic currency said the problem was with Mt. Gox, not with the revolutionary Bitcoin currency itself. Six leading Bitcoin exchanges, including Coinbase, Kraken and Bitstamp distanced themselves from Mt. Gox.

"This tragic violation of the trust of users was the result of one company's actions and does not reflect the resilience or value of Bitcoin and the digital currency industry," they said in a joint statement.

"As with any new industry, there are certain bad actors that need to be weeded out, and that's what we're seeing today," they added.

Mark Karpeles told Reuters news agency the bitcoin exchange was "at a turning point".

On Tuesday afternoon, the website said laconically: "In the event of recent news reports and the potential repercussions on MtGox's operations and the market, a decision was taken to close all transactions for the time being in order to protect the site and our users. We will be closely monitoring the situation and will react accordingly." No further content was accessible.

hg/dr (AP, Reuters)