Hackers behind one of the biggest ever cryptocurrency heists have returned more than a third of US$613 million (RM2.6 billion) in digital coins they stole, the company at the centre of the hack said on Wednesday.

Poly Network, a decentralised finance platform that facilitates peer-to-peer transactions, said on Twitter that US$260 million (RM1.1 billion) of the stolen funds had been returned but that US$353 million (RM1.5 billion) was outstanding.

The company, which allows users to swap tokens across different blockchains, said on Tuesday it had been hacked and urged the culprits to...