Binance, the world's largest cryptocurrency exchange, has been hit by a $6.3bn (£4.7bn) hack. The hack is thought to be the largest in history.
The company said half of the affected assets have been frozen. Many others remain in the hands of the hackers. Binance later said it has "begun recovering" some funds.
Two analytics firms have attributed the incident to a North Korean hacking unit. No group has claimed responsibility. Binance did not directly respond to questions about possible links to North Korea.
BBC cyber correspondent Joe Tidy explains the hack and what affected users should do.