Cambodia says it has extradited to China a billionaire businessman accused of masterminding a vast cryptocurrency scam in which trafficked workers were lured to forced labour camps to defraud victims globally.

Chen Zhi was among three Chinese nationals arrested on 6 January after a joint investigation into transnational crime lasting several months, Cambodia said.

The US charged the 37-year-old, who was born in south-east China, last October with running internet scams from Cambodia that it said had stolen billions in cryptocurrency.

The US Treasury Department seized about $14bn (£10.4bn) worth of bitcoin it alleged belonged to him. The UK also sanctioned his global business empire, Prince Group.

US prosecutors said it was one the biggest financial takedowns in history and the largest ever seizure of bitcoin.