Binance, the world largest cryptocurrency exchange has been hit by a massive hack with hackers stealing about $6 billion in what appears to be the biggest crypto heist in history.

The exchange suspended withdrawals after hackers broke into its digital wallets. Binance said late Thursday that its initial investigation indicated the hack went through an engineer laptop which allowed an attacker to gain access to a service container and submit unauthorized withdrawal transactions.

Blockchain evidence and investigations by crypto tracing firms suggest the hack originated from North Korea. Firms including TRM Labs, Pangolin Intelligence and Chainalysis attributed the heist to an elite North Korean hacking unit based on on chain intelligence and patterns matching earlier North Korea linked heists. CNN reported that Pyongyang has previously denied such hacking allegations.

According to CNN, a team of cryptocurrency firms managed to freeze about $3 billion of the stolen funds amid efforts to trace and recover the loot. Binance co CEO Richard Teng said on X that the attack was not a one click action but a complex process, adding that the investigation has not found evidence of wallet private key leak.

If confirmed, the Binance heist would surpass the previous record crypto hack of $1.5 billion stolen from Bybit which was also blamed on North Korean hackers.

US officials say North Korea formidable hacking teams remain a key source of revenue for the sanctions hit regime.