Bitcoinica noted that the stolen bitcoins belonged to the exchange, not the users, and said it will honor any withdrawal request. However, it's not clear when or if the website will resume operations.

"It's more serious than we thought," said Bitcoinica founder Zhou Tong, in on the Bitcointalk forum on Saturday. "Likely we will either shut down the platform or re-develop entirely (which will take months instead of days)."

The company needs more time to come up with a plan to compensate users for the downtime and other issues resulting from this security incident, Zhou said.

In on Sunday, Zhou revealed that he sold Bitcoinica to an undisclosed investor back in November 2011 and stayed with the company as an employee in charge of daily operations until a new team took over two weeks ago. He also announced that he plans to retire from all bitcoin-related projects after this incident is resolved.

Security breaches at bitcoin exchanges don't only affect the users of those exchanges, but the entire bitcoin community, because they negatively affect the value of the virtual currency. In June 2011, bitcoin prices plummeted after news broke that the largest bitcoin exchange, Mt.Gox, was compromised.