A financial industry group is warning members to be on the lookout for digital threats amid slowdowns at the websites of two of the nation's biggest banks.

The Financial Services Information Sharing and Analysis Center, known as FS-ISAC, raised its cyber threat level to "high" from "elevated" in an advisory to members Wednesday.

Both Bank of America (BAC) and JPMorgan Chase (JPM) said this week that some customers who tried to log on to their websites encountered delays.

FS-ISAC counseled members to "maintain a heightened level of awareness" following "recent credible intelligence" regarding the potential for cyberattacks against financial institutions.

The admonition followed an alert Monday by the FBI, which warned financial firms that thieves may be attacking their websites to steal information that could be used to make fraudulent wire transfers.

For their part, both Bank of America and JPMorgan Chase said customers continue to be able to bank online.

"Chase.com is up, but some customers are having trouble getting to us," bank spokesman Mike Fusco told American Banker on Thursday. "We're working on it and apologize for the frustration. As always, customers can call us or stop by a branch or ATM to do their banking. "

Bank of America spokesman Mark Pipitone told American Banker on Thursday: "Our online banking site is up and running."

On Tuesday, a group of self-described digital warriors threatened to attack Bank of America and the New York Stock Exchange (NYX) in retaliation for an American-made, anti-Islamic film that sparked violent protests recently across the Muslim world. "This attack will continue till the Erasing of that nasty movie," someone named Cyber fighters of Izz ad-din Al qassam posted Pastebin.com, a website used by programmers.