Amazon.com Inc. said it fired an employee who disclosed customer email addresses to a third-party merchant on the site in violation of the e-commerce giant’s policies.

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

Amazon (AMZN) alerted the shoppers, although the company said no action such as changing passwords was needed, according to a notice sent to the customers. It didn’t disclose how many customers were affected.

No other information was disclosed, and the merchant has been blocked from the website, the Seattle-based company said.