Hacktivists who claim responsibility for a series of cyberattacks on some of the nation's biggest banks are vowing to continue the offensive.

The al Qassam Cyber Fighters Group, which threatened on Dec. 10 to launch so-called denial of service attacks against JPMorgan Chase (JPM), Bank of America (BAC), U.S. Bank (USB), PNC (PNC) and SunTrust (STI), is pointing to recent attacks on two of them as evidence of its ability to strike again.

Both U.S. Bank and PNC said Thursday their websites had been hit by a torrent of requests that could delay access for some customers.

"The attacks of this week will be as wide as previous week," the group wrote Tuesday in a message posted on Pastebin, a website used by programmers.  "The 5 major US banks will be attacked and we subsequently suggest that from now on they prepare their context of sorrowfulness to the customers of banks because of inaccessibility."

The group has pledged to maintain the assaults, which flood banks' websites, as long as a trailer for "The Innocence of Muslims," an American-made, anti-Muslim film, remains posted on YouTube.

The group also posted the email interview they gave to American Banker last month.

A SunTrust spokesman declined to comment. Spokesmen for the other banks did not respond immediately to a request for comment.