WASHINGTON—U.S. regulators are stepping up calls for banks to better-arm themselves against the growing online threat hackers and criminal organizations pose to individual institutions and the financial system as a whole.

The push comes as government officials grow increasingly concerned about the ability of a cyber attack to cause significant disruptions to the financial system. Banks such as J.P. Morgan Chase & Co., Bank of America Corp. BAC +1.07% and Capital One Financial Corp. COF +1.62% have been targeted by cyber assaults in recent years, including potent “denial-of-service” strikes that took down some bank websites off-and-on for days, frustrating customers. Banks have spent millions of dollars responding to or protecting against such attacks, including a wave of attempted online assaults targeting major banks beginning last year that U.S. defense officials say had the backing of the Iranian government.

SOURCE: online.wsj.com