Wells Fargo customers may have a hard time getting an up-to-date balance statement Tuesday as the nations' fifth-largest bank continued to iron out service problems related to a Sunday computer failure.

The outage knocked the company's Internet, telephone, and ATM banking services offline for several hours, and Wells Fargo customers continued to experience problems into Tuesday.

Wells Fargo didn't offer many details about the system failure, but it was serious enough that the company had to restore from backup. "Using our back-up facilities, we restored Internet banking service in about one hour and 40 minutes," the company said in a statement, released Tuesday. "We thank the hundreds of team members in our technology group for working so hard to resolve this problem."

Other banking services such as point-of sales transactions, loan processing, and wire transfers were also affected by the outage, and while all systems are now fully operational, some customers may continue to see their Friday bank balances until the end of Tuesday, Wells Fargo said.

Though customers couldn't perform transactions during the outage, the company's Web site was not knocked offline, according to data from Web analysis firm Netcraft.

"We apologize for the inconvenience this caused them," the Wells Fargo statement said. The company did not return a telephone message seeking additional information about the outage.

With about 160,000 employees, Wells Fargo operates nearly 7,000 ATMs and almost 6,000 stores nationwide.