NEW YORK (Reuters) -Industrial and Commercial Bank of China's hack left its U.S. unit temporarily owing Bank of New York Mellon $9 billion as a result of unsettled trades, prompting the parent to inject capital into the unit to settle the trades, sources familiar with the matter said. The attack, confirmed by ICBC on Thursday, is the latest in a string of ransom demands by hackers this year. ICBC Financial Services, the bank's U.S. unit, said on Thursday it was investigating the attack that disrupted some of its systems, and making progress toward recovering from it.