A computer system used by Hillary Clinton's presidential campaign was , a spokesman for the Democratic presidential nominee said Friday.
Nick Merrill said in a statement that the cyber breach was part of a larger hack attack on the Democratic National Committee (DNC) that was made public earlier this week.
The violation conceed a DNC analytics data program used by the Clinton campaign and "a number of other entities," Merrill said. He added that security experts hired by the campaign had found "no evidence" that the campaign's inteal systems were compromised.
Soruces familiar with the incident confirmed to Fox News that the FBI is investigating the breach as well as another cyberattack on the Democratic Congressional Campaign Committee (DCCC).
The investigation was first reported by Reuters, which said that the Justice Department's national security division was investigating whether the cyberattacks threatened the U.S.
An FBI statement did not mention the Clinton campaign specifically, but said it was aware of reporting "on cyber intrusions involving multiple political entities, and is working to determine the accuracy, nature and scope of these matters."
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The report that Clinton's campaign was comes the same day that the cyberattack on the DCCC, which raises money for Democratic congressional candidates, was made public. Sources told Fox News Friday that the DCCC hack bears similarities to the breach of DNC files.
The DNC breach led to the embarrassing leak of inteal emails by WikiLeaks that appeared to show a pro-Clinton bias in the organization -- and, in tu, led to DNC Chairwoman Debbie Wasserman Schultz stepping down ahead of this week's Democratic National Convention.
The hack of the DCCC’s web server allowed the hackers to create and redirect traffic to a fake donations page, made to look and feel authentic, sources said. From there, hackers were able to capture all data entered on the page. Sources said the objective behind the hack is not clear, though it could be to harvest data on Democratic donors and supporters.
Additionally, Fox News has obtained analysis of the DCCC hack from private sector cybersecurity firm FireEye that suggests the intrusion was carried out by a Russian-govement aligned hacking group dubbed "Tsar Team (APT28)."
In its research, FireEye notes it previously confirmed that malware analyzed from the DNC hack was also consistent with "Tsar Team" -- suggesting the group was involved in both attacks.
Tsar Team has also been implicated by FireEye in numerous cyberattacks aimed at foreign targets on behalf of the Russian govement in the past.
Fox News' Matt Dean, Serafin Gomez and the Associated Press contributed to this report.