The Democratic party has been attacked by hackers a third time, it was reported Friday afternoon, and this time it was Hillary Clinton's presidential campaign that took a direct hit.

The latest hack follows high-profile breaches involving the Democratic National Committee (DNC) and the Democratic Congressional Campaign Committee (DCCC), the campaign arm for House Democrats.

Russia is the leading suspect in the hacks, with some fearing the country is aiming to influence the outcome of the forthcoming election. The Russian government has vehemently denied involvement.

Donald Trump called on Russia to essentially hack the Clinton campaign earlier in the week after the first breach was revealed, something he later dismissed as sarcasm.

Nick Merrill, Clinton's press secretary, said that a data program used by the campaign was accessed as part of the wider DNC hack but insisted that there was "no evidence that our internal systems have been compromised."

Clinton campaign statement on hack via @NickMerrill: "No evidence that our internal systems have been compromised" pic.twitter.com/0vrE22SVas — Monica Alba (@albamonica) July 29, 2016

President Barack Obama has said Russia was almost certainly responsible for the hack of the Democratic National Committee, an assertion with which cybersecurity experts have agreed.

That breach led to the release by WikiLeaks on July 22, days before the Democratic convention began, of 19,000 emails showing that supposedly neutral party officials were favoring Clinton over Vermont Sen. Bernie Sanders during their primary contest for the presidential nomination.

The congressional campaign committee is working with the FBI and CrowdStrike Inc., a computer security firm based in Irvine, California to investigate the breach.

CrowdStrike and another security firm, ThreatConnect Inc. of Arlington, Virginia, said they found evidence pointing to Russian government involvement in the DNC hack when they analyzed the hackers' methods and efforts to distribute the stolen emails and other files.

The hacker groups, identified by CrowdStrike as Cozy Bear and Fancy Bear, used different but sophisticated techniques to break into the DNC and try to avoid detection.

Additional reporting by the Associated Press.