The government is launching a program nicknamed Perfect Citizen to detect cyber assaults on private U.S. companies and government agencies running critical infrastructure such as the electricity grid and nuclear power plants, the Wall Street Journal said in its online edition, citing people familiar with the program.

The surveillance by the National Security Agency would rely on sensors deployed in computer networks for critical infrastructure that would be triggered by unusual activity suggesting an impending cyber attack, the sources said.

Defense contractor Raytheon Co recently won a classified contract for the initial phase of the surveillance effort valued at up to $100 million, a person familiar with the project told the Journal.

A National Security Agency spokeswoman declined to provide comment to Reuters on the report. Representatives of the Department of Homeland Security and Raytheon did not immediately reply to Reuters requests to comment on the Journal report.

(Reporting by Ransdell Pierson and Jim Wolf; editing by Andre Grenon)