A senior administration official says that the U.S. has “high confidence” ‎that it was the G.R.U. -- Russia’s largest intelligence agency -- that conducted the hacking of the DNC and DCCC with goal of giving an advantage to Donald Trump.

The U.S. government is likely to sanction the G.R.U. leadership as a punitive response.

Sources told CBS News homeland security correspondent Jeff Pegues that elements of the Republican National Committee (RNC) apparatus were hacked, but the damage was not as widespread as the hacks that affected the Democratic National Committee (DNC).

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While the CIA has high confidence that the Russians tried to influence the presidential election and in favor of Donald Trump, the FBI has not reached a consensus with the CIA on this. Some intelligence officials, Pegues reported, are puzzled about leaks from the FBI casting doubts on the intelligence community’s assessment, given that typically, the intelligence community and the FBI try to come to a consensus before going public with big investigations like this.

A law enforcement source told CBS News that the FBI is not necessarily at odds with CIA findings, but its investigation into the hacking of the DNC is still ongoing. The source also pointed out that the two agencies collect information for different ends -- the CIA does assessments, while the FBI collects evidence for prosecutions that must hold up in court.

CBS News senior investigative producer Pat Milton contributed to this report.