Library of Congress email system hacked earlier this year by 'foreign adversary'

The Library of Congress email system suffered a substantial hack earlier this year by a "foreign adversary," Fox News can confirm.

It is unclear if the hack compromised accounts of those who work directly for the House and Senate.

However, Fox News is told that U.S. Capitol Police has referred the matter to the FBI, and it is investigating the scope of the hack.

This is a developing story. Please check back here for more updates.