America's intelligence chief said on Thursday that China was the top suspect in a hack of a U.S. agency that compromised the personnel records of millions of Americans, the Wall Street Journal reported on Thursday.

The comments from Director of National Intelligence (DNI) James Clapper marked a departure of sorts for the Obama administration, which has avoided publicly pointing to Beijing, even as officials said privately China likely was behind the attack.

"You have to kind of salute the Chinese for what they did," given the difficulty of the intrusion, the Journal quoted Clapper as saying at a Washington intelligence conference.