Bitcoin dropped below $20,000 on Saturday to its lowest level in 18 months, extending its slide as investors pull back from riskier assets amid rising interest rates.

The biggest cryptocurrency was down 7.1 per cent to $18,993 at 0906 GMT, having earlier touched $18,732, its lowest since December 2020.

It is down about 59 per cent this year, while rival cryptocurrency Ethereum-backed ether is down 73 per cent.

The digital currency sector has been pummelled this week after cryptocurrency lending company Celsius froze withdrawals and transfers between accounts.

The sector has also suffered losses after companies such as Coinbase Global Inc, Gemini and Blockfi said they would lay off thousands of employees as investors ditch risky assets.