The White House is investigating the use of private email servers by top officials

The White House is investigating the email practices of top officials, Politico reported on Thursday, after news surfaced that six White House senior aides used private email servers for government business.

As part of the internal probe, the White House is reportedly pulling batches of emails on the White House server to and from the aides' private accounts. The office of the White House counsel is reviewing the email accounts to find possible messages related to ongoing federal investigations, such as Robert Mueller's investigation into Russian collusion in the 2016 election.

Last week, Politico reported that White House senior adviser Jared Kushner sent or received about 100 government-related emails from a private account. Subsequent reporting by Newsweek and The New York Times found that five other White House aides also used private emails for government business, including current aides Ivanka Trump, Gary Cohn, and Stephen Miller.

The investigation could take months to complete, according to the Politico report, which cited four officials familiar with the matter. One of the officials told Politico that news of the private email use angered White House officials and caught White House lawyers by surprise.

It is not illegal for White House advisers to use private email accounts, but any work-related emails must be forwarded to their government accounts so they can be preserved and made available to the public.