Ben Fox Rubin/CNET

An Amazon employee was fired after sharing customers' email addresses with an unnamed third-party seller, in violation of company policies, Amazon said.

"The individual responsible for this incident has been terminated from their position, and we are supporting law enforcement in their prosecution," an Amazon spokesperson said in a statement Friday.

Amazon said only email addresses were taken by the employee, not any other customer information. The company has already started emailing affected customers about the incident.

A third-party seller is a merchant that sells on Amazon's website, though the company declined to provide additional information about this seller. It said the seller has been blocked from Amazon.

Enlarge Image Via Twitter

Amazon also declined to provide additional information about the employee, when it discovered the issue or how many people were affected.

Maintaining customer data is a vital part of Amazon's business, since it holds personal information, including credit and debit card numbers, for over 300 million accounts worldwide.

The firing comes a few weeks after The Wall Street Journal reported on Amazon investigating alleged data leaks at the company, which included employees allegedly selling customers' email addresses to sellers. The report said the practice was more prevalent in China. It's unclear whether the firing is directly connected to the previously reported investigations.

The company said that if customers receive unsolicited emails from a seller, they can forward the email to report-abuse@amazon.com.

NASA turns 60: The space agency has taken humanity farther than anyone else, and it has plans to go further.

Taking It to Extremes: Mix insane situations -- erupting volcanoes, nuclear meltdowns, 30-foot waves -- with everyday tech. Here's what happens.