Bitstamp, a bitcoin exchange service, has suspended its services while it investigates a possible breach in its security.

Bitstamp going offline has frozen up users accounts and it making it unable for them to transfer money. The service has warned users that they should stop trying to deposit funds into their accounts while it’s offline, reports Wired.

The possible security breach took place over the weekend and may have affected some of Bitstamp’s stored funds. The service has announced much about the possible security breach , but said it will starts its services again when it has learned more about the issue, Wired notes.

“To restate: the bulk of our bitcoin are in cold storage, and remain completely safe.,” Nejc Kodrič, CEO of Bitstamp, said in a Tweet.

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