Bank of America's (BAC) online and mobile banking halted for nearly half the day on Friday, leaving customers unable to access their accounts.

The nation's second biggest bank by assets took to Twitter and Facebook at roughly 1:30 p.m. Eastern to say that it was experiencing "technical issues" as customers complained of being unable to bank via the Web or smartphones.

Trouble with the bank's computers is believed to have caused the interruption, which lasted for roughly 10 hours. B of A said its ATMs and credit and debit cards functioned through the failure.

"Our online and mobile banking platforms are coming back up," B of A tweeted at 11:29 p.m.Eastern. "We will continue to monitor throughout the night to make sure you get the service you expect from us and that you deserve."

B of A said Saturday morning that the platforms had resumed running normally although the bank continued to monitor them closely.

Though the outage follows a series of cyberattacks that disrupted online banking at  some of the nation's biggest banks, a source close to the situation said the cause was an internal systems issue. A group that has claimed responsibility for the attacks suspended its campaign recently.

B of A told customers their logins, passwords and account information remained safe despite the service glitch.