An online Bitcoin exchange based in the Czech Republic has been targeted by hackers who emptied the wallets of 4,000 users.

According to the Czech news site, approximately 4,000 bitcoin wallets had been opened by the hackers. The wallets are estimated to have contained a total value of over 2 million Czech koruna which equates to £62,000.

Czech Bitcoin Exchange Hacked
4,000 wallets were emptied in the online attack at a cost of £62,000 (Reuters)

The digital currency site is currently down with a maintenance message:

"Server was attacked by hackers. On 11.11. in the evening it was broken by server security and thefts to Bitcoin wallets resulted. Unfortunately, the nightmare became reality. We will keep you informed."

"Due to the ongoing investigation, we cannot further comment on specific questions about the attack.

As soon as circumstances permit us, we will publish more information ... Thanks to all who despite the loss posted messages expressing support us."

Must Read: What is Bitcoin and how does it work?

The website claimed that its security system was broken and clients' bitcoins were stolen on Monday.

In a statement stated that it has filed a lawsuit against the anonymous hackers.

Bitcoin is a decentralised, digital cryptocurrency which its supporters claim to be counterfeit-proof.

The news comes just days after a Chinese exchange vanished, taking over £2.5m worth of coins with it and an Austrian Bitcoin owner reported a theft of approximately £700,000 worth of coins from his online wallet.

One might think that money evaporating into the ether would be bad for bitcoin, but exchange MtGox's exchange rate between the US dollar and the crypto-currency has actually improved in Bitcoin's favour over the last week.

Bitcoin was trading at a high of $389 as of Wednesday afternoon.