Amazon.com's Web site went down for several hours on Friday.

Amazon.com became unavailable Friday morning and was still out of service at 3 p.m. A message saying "Http/1.1 Service Unavailable" appeared when visitors attempted to open the homepage from search engines.

Typing the address "https://amazon.com" appeared to bring up the homepage. However, links still failed most of the time and produced the following message: "We're sorry! An error occurred when we tried to process your request. Rest assured, we're already working on the problem and expect to resolve it shortly. If you were trying to make a purchase, please check Your Account to confirm that the order was placed. We apologize for the inconvenience."

Media reports and blogs indicated that users outside of the United States could access the site for most of the day.

Representatives from the company could not be reached immediately for comment.

A discussion forum for sellers contained a post explaining that the company's engineers were working on an issue that has impacted the site's availability. The post was listed as "Amazon Unplanned Event 06/06). It was signed "Technical Account Management."

"Greetings from Amazon.com," the post began. "We are currently investigating an issue that has impacted the availability of the Amazon.com website. Engineers are actively engaged in resolving this issue and we will provide an update once the issue is resolved. We appreciate your patience during this time."

On June 4, the company had problems with its seller accounts. Sellers were unable to access a feature allowing them to view their inventory. According to the seller community posts, Amazon has suffered dozens of "unplanned events" in the last several weeks, with most affecting seller account features. None appeared to completely stop buyers from using the site, as Friday's outage did.