The hacker drained the bridge of 173,600 Ether and 25.5 million USDC tokens in two transactions, Ronin said.

In one of the largest crypto industry attacks ever, the Ronin Bridge that connects different blockchains revealed that hackers stole about $590 million.

Computers known as nodes operated by Axie Infinity maker Sky Mavis and the Axie DAO that support the bridge — a piece of software that lets people easily convert tokens into ones that can be used on the Ronin network — were attacked, with the hacker draining the bridge of 173,600 Ether and 25.5 million USDC in two transactions, Ronin said. The breach happened on March 23, but was only discovered Tuesday, Ronin revealed.

The attack is the latest to show that bridges are often rife with problems. Many bridges’ code isn’t audited. It’s often unclear who runs them and exactly how. Identities of validators, who are supposed to order transactions on bridges, are often shrouded in mystery.

The price of Ron, a token used on the Ronin blockchain, dropped about 20% after the hack was disclosed. AXS, a token used in Axie Infinity, fell 6%, per CoinMarketCap.

Ronin didn’t immediately return requests for comment.

In its blog, Ronin said it’s in touch with major cryptocurrency exchanges and with blockchain tracer Chainalysis to monitor the move of the stolen funds. Ronin also said it’s working with law enforcement.