Binance said it was investigating a suspected cyberattack and froze about $3 billion in crypto assets as a precaution to prevent theft. It suspended trading in some products and said there was no confirmed impact on users’ funds; the scale of any damage remained unclear. Co-founder Yi He said the company would reimburse losses caused by hacks.

Tether said it had frozen more than $1.5 billion in assets, while Circle said it had frozen more than $800 million in coordination with law enforcement. Cryptocurrency prices fell following the reports, with bitcoin dropping to about $77,500 and ether below $2,200.