House Republican Campaign Committee Says It Was Hacked This Year

WASHINGTON — The campaign committee for House Republicans discovered in April that the email accounts of several of its senior officials had been hacked by what analysts later concluded was a “foreign entity,” people who have been briefed on the case said on Tuesday, highlighting the continued vulnerability of the United States to interference in its elections.

The hack of the organization, the National Republican Congressional Committee, exposed thousands of emails from four senior aides for months, and perhaps longer. The hack was terminated when the staff members, alerted to the intrusion, changed their passwords. The committee called in the F.B.I. to investigate.

But the committee waited eight months — until after Republicans lost 40 seats and control of the House of Representatives in the midterm elections — to disclose publicly what had happened. It remains unclear who was behind the hack.