Another one of the nation's biggest banks has experienced a digital disruption.

Wells Fargo (WFC) said Tuesday that some of its customers had trouble logging on to its website, roughly a week after online customers of Bank of America (BAC) and JPMorgan Chase (JPM) encountered similar delays.

"We apologize to customers who may be experiencing limited access to & online banking," Wells Fargo tweeted Tuesday. "We are working to quickly resolve this issue."

Wells Fargo, which posted a similar message on Facebook, said customers still could access their accounts via the bank's ATMs or phone, or by visiting its branches.

The slowdown comes a week after someone threatened to attack both Bank of America and the New York Stock Exchange (NYX) in retaliation for the "Innocence of Muslims," an American-made, anti-Islamic film. It also follows a report that hackers from Iran may have targeted the biggest U.S. banks as part of a broader cyber offensive against the United States.

The Financial Services Information Sharing and Analysis Center, an industry group, has boosted its cyber threat level to "high" from "elevated" and urged members to monitor their networks carefully. The FBI warned recently thieves may be trying to steal information from financial firms' websites that could be used to make fraudulent wire transfers.

The White House is said to be considering directing federal agencies to adopt guidelines for cybersecurity at power plants, water treatment facilities and other critical infrastructure, Reuters reported Tuesday. The executive order would incorporate elements of a bill that failed to clear the Senate in August following a filibuster.