The initial attempts to hack the DNC and other Democratic Party groups go back as early as July of 2015, an individual familiar with the situation told CBS News.

A group nicknamed Cozy Bear -- also referred to as “The Dukes” and “APT 29” -- began its campaign with what is described as a “wide target set,” which involves making hundreds of attempts (if not more) to initiate a hack and to infiltrate servers of Democratic Party-related infrastructure.

This information follows the news this week that the U.S. has “high confidence” ‎that it was the G.R.U. -- Russia’s largest intelligence agency -- that hacked both the DNC and the DCCC, with the goal of boosting President-elect Donald Trump’s candidacy. This issue is likely to remain in the spotlight -- especially because ExxonMobil CEO Rex Tillerson, Mr. Trump’s pick for secretary of state, has extensive ties to Russia.

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Sources told CBS News on Monday 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). RNC officials have denied that the organization was hacked.

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, sources said, 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.