WASHINGTON — The Library of Congress has informed lawmakers of a “cyber breach” of its computer system by an adversary, a hack of emails between some congressional offices and library staff, according to an email obtained by the Library of Congress. ‘Associated Press.

The library said an adversary accessed email communications between January and September.

The matter was referred to law enforcement, the library said. Authorities did not immediately provide any information about the attacker, including whether his identity was known.

“The library has mitigated the vulnerability used by the adversary to access the environment and has taken steps to prevent such incidents in the future,” the library said in the notification.

NBC News was first to report the breach.

The Library of Congress operates across the street from the United States Capitol in the complex. It is the largest library in the world, according to its website, and contains “millions of books, films and videos, audio recordings, photographs, diaries, maps and manuscripts in its collections”.

The library is also the primary research arm of Congress and the headquarters of the U.S. Copyright Office.

In the notification regarding the breach, the library noted that the House and Senate computer networks, “including individual House and Senate email accounts, were not compromised in any way.”

It states that “an adversary accessed email communications between congressional offices and certain library staff, including the Congressional Research Service, compromising information obtained in those emails.”

The notifications indicate that the US Copyright Office’s systems were not affected by the violation.

The library said it is analyzing the email communications viewed and will contact specific congressional offices and staff members for more information.