The head of leading bitcoin exchange, Mt. Gox, says that it is working to resolve the issues that led to its recent shutdown.

In a notice posted on the organization’s website, Mark Karpeles, Mt. Gox chief executive, says, “As there is a lot of speculation regarding Mt. Gox and its future, I would like to use this opportunity to reassure everyone that I am still in Japan, and working very hard with the support of different parties to find a solution to our recent issues.”

The exchange has stopped all transactions in the wake of reports that it has lost hundreds of thousands of bitcoins. Karpeles also noted that Mt. Gox staff have been instructed not to answer any questions, or give any information about its situation.

In the wake of the shutdown, bitcoin derivatives exchange BTC.SX said that it has also suspended its operations, “due to the current closure of our main exchange partner.”

“All customer balances are secure and we will honour any withdrawal requests,” it said, adding that open positions will be liquidated and deposits refunded. It is hoping to reopen at some point, saying, “… we are working hard to integrate new exchanges and offer our service again as soon as possible.”