TOKYO (AP) — The Mt. Gox bitcoin exchange in Tokyo has filed for bankruptcy protection, acknowledging that a significant amount of the virtual currency has gone missing.

The exchange's CEO Mark Karpeles appeared before Japanese TV news cameras today, bowing deeply for several minutes.

He saysa weakness in the exchange's systems was behind the massive loss of the virtual currency.

Speaking in Japanese at a Tokyo court, he apologized for the troubles he had caused so many people.

Kyodo News says debts at Mt. Gox totaled more than 6.5 billion yen ($65 million), surpassing its assets.

The exchange's unplugging this week drew renewed regulatory attention to a currency created in 2009 as a way to make transactions across borders without third parties such as banks.