Google Inc. (GOOG) said Thursday a service disruption that affected a small subset of Gmail users "should be resolved."

The Internet giant did not immediately provide details about the cause or the scope of the disruption, which lasted for a few hours and was the second outage to hit the popular email service this month.

"A problem with Google Contacts caused many Gmail users to experience slowness and degraded service for about an hour today. Mail was back to full speed for everyone around 8 a.m. Pacific and the issue affecting Contacts was resolved shortly after," a Google spokesperson said in an email.

The company acknowledged the issue at about 7:30 a.m. Pacific time (10:30 a.m. EDT) and provided readers with a work-around solution to access their accounts.

The disruption follows similar issues that have affected Gmail users in recent months. In February, Google mail users around the world were locked out of their accounts for up to 24 hours after the company introduced new software that triggered a bug in the email program's code.

Gmail went down for about an hour and 45 minutes on Sept. 1, during which time users could access their email only through third-party applications such as Microsoft Outlook. A company executive apologized after that incident in a blog post, saying the outage was "a Big Deal."

The latest service glitch, while apparently much smaller than earlier outages, will likely increase concerns about the reliability of Web-based software, which Google is promoting as an alternative to Microsoft Corp.'s (MSFT) packaged products.

Shares in Google were down $2.55, or 0.6%, at $495.70.

-By Scott Morrison, Dow Jones Newswires; 415-765-6118; scott.morrison@dowjones.com