Several U.S. government agencies have been hit in a global hacking campaign that exploited a vulnerability in widely used software, the U.S. cyber watchdog agency said Thursday.

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) said several federal agencies had experienced intrusions following the discovery of a weakness in the file transfer software MOVEit, Eric Goldstein, the agency's executive assistant director for cybersecurity, said in a statement.

"We are working urgently to understand impacts and ensure timely remediation," he said.

CISA did not immediately return emails seeking further comment. The FBI and U.S. National Security Agency also did not immediately return emails seeking details on the breaches.

The United States does not expect any "significant impact" from a cyberattack that hit its government agencies, Jen Easterly, the director of the U.S. Cybersecurity and Infrastructure Security Agency, told MSNBC.

The agency was working to fully figure out the attack's impact and coordinating with other agencies to ensure a remediation, Easterly said.

(Reporting by Raphael Satter and Shivani Tanna; editing by Jonathan Oatis and Angus MacSwan)