The Industrial and Commercial Bank of China¡¯s (ICBC) U.S. arm was hit by a ransomware attack that disrupted trades in the U.S. Treasury on Thursday, the latest in a string of victims ransom-demanding hackers have claimed this year.

ICBC Financial Services, the U.S. unit of China¡¯s largest commercial lender by assets, said it was investigating the attack that disrupted some of its systems, and making progress toward recovering from it.

Hackers lock up a victim organization¡¯s systems in such attacks and demand ransom for unlocking it, often also stealing sensitive data for extortion.