One of the largest cryptocurrency exchanges in the world, Binance, on Wednesday said that hackers have withdrawn 7,000 Bitcoins through a single transaction after a "large scale security breach."

According to calculations by Bloomberg, the 7,000 Bitcoins are roughly worth $40 million, based on current Bitcoin composite pricing.

Bitcoin composite pricing hit a new 2019 high on Tuesday morning (London time) to $5,961, approaching the $6,000 level for the first time since November 2018. Following the theft incident, it fell by 3.1 percent to a low of $5,665 on Wednesday morning (Hong Kong time).

In a post on its website, Binance said that the hackers used a "variety of techniques" that include phishing and viruses to obtain a large amount of data. It also said there may be additional accounts affected that it hasn't identified yet.

The post said that the transactions were limited to Binance's BTC hot wallet, which contains about 2 percent of the company's Bitcoin holdings, while other wallets are secure and unharmed.

The hackers structured the transaction in a way that it could bypass existing security checks in place and Binance was unable to block the withdrawal before it was executed, the exchange said. On executing the transaction, alarms were triggered on Binance's system and all withdrawals were stopped immediately after that, it said.

Binance estimates that the security review of its systems and data, that it intends to do, will take a week's time and during this time all deposits and withdrawals will remain suspended, however, trading will continue to be enabled to allow investors to adjust their positions.