PayPal was hit by an outage early this morning that prevented customers from using the online payment service for more than an hour.

The outage started at 12:11 am PT, according to PayPal's Developer Network. PayPal said it was resolved by 1:23 a.m. PT, though the company acknowledged that access to international PayPal sites, such as ones in the U.K. and Spain, may have been slow or intermittent until 2 a.m. PT

The outage prevented customers from logging into their PayPal accounts. But the company said it didn't affect the ability of merchants to use PayPal's API services through which they integrate the PayPal payment option into their own online checkout systems.

PayPal schedules regular maintenance each Thursday and Friday from 11 p.m. to 1 a.m. PT, but such maintenance rarely leads to downtime, according to Netcraft, a provider of Internet services.

A PayPal representative sent CNET a short, very general statement later this morning, blaming the outage on a "software issue discovered during routine maintenance." CNET has requested more details.

This is what PayPal posted about its outage.

Updated at 9:20 a.m. PT with a statement from PayPal.