The group for DoS attacks against Bank of America, JPMorgan Chase and Citigroup Inc. that disrupted online operations, and said the attacks would continue "until the Erasing of that nasty movie" -- a reference to a trailer of the independent film "Innocence of Muslims," which Muslims say insults the Prophet Muhammed.

This week, it said it had conducted and that its next targets would be U.S. Bancorp and PNC Financial Services. Reports saying customers of those two institutions were having trouble accessing their websites.

Since the attacks began, about the source.

U.S. Sen. Joseph Lieberman (I-Conn), chairman of the Senate Homeland Security Committee, said last week in an that he believed a unit of Iran's Revolutionary Guard Corps was behind them.

Also last week, the FBI issued a fraud alert, warning financial services firms that cybercriminals might try to disrupt their websites in an effort to .