UNDATED -- A financial services security group is warning about possible cyber-attacks on banks, citing "recent credible intelligence."

The group, the Financial Services Information Sharing and Analysis Center, has raised its cyber threat level to "high" from "elevated," saying there is potential for attacks that could make companies' websites unusable for customers.

The group told companies to "maintain a heightened level of awareness."

JPMorgan Chase & Co. and Bank of America have both acknowledged problems with their websites this week, but haven't commented on the reasons. Some Internet outlets have speculated that the outages are the work of terrorists.

The financial services security group was created in 1999 by a government order to help banks prepare for Y2K.