The computer system of the Democratic National Committee in Washington, D.C., was hacked by Russian government groups, the DNC and security officials said last month. The FBI announced Monday it was investigating the hacking. Photo by bmw328driver/Flickr

WASHINGTON, July 25 (UPI) -- The FBI is investigating the hacking of the Democratic National Committee's emails allegedly linked to the Russian government, the bureau announced Monday.

"The FBI is investigating a cyber intrusion involving the DNC and are working to determine the nature and scope of the matter," the bureau said in a statement. "A compromise of this nature is something we take very seriously, and the FBI will continue to investigate and hold accountable those who pose a threat in cyberspace."


On Friday, Wikileaks released national committee emails that suggested favortism of Hillary Clinton and ways to hurt Bernie Sanders during the primaries.

Clinton's campaign manager Robby Mook said that analysts have concluded the hack was "perpetrated by Russian state actors" as a way to help Republican nominee Donald Trump. Speaking at a Bloomberg Politics breakfast Monday in Philadelphia, Mook said Trump has taken stances that might be supported in Russia

Trump mocked allegations that Putin was involved, tweeting, "The new joke in town is that Russia leaked the disastrous DNC e-mails, which should never have been written (stupid), because Putin likes me."

John Podesta, Clinton's campaign chairman, said Monday on MSNBC's Morning Joe, "what we have is a kind of bromance going on between Putin and Trump which is distinct from this leak."

Democratic officials and cybersecurity company CrowdStrike Inc. said last month that hackers linked to the Russian government accessed DNC servers. On Friday, almost 20,000 emails and other documents stolen in the attack were posted online by WikiLeaks. On Sunday, DNC Chairwoman Debbie Wasserman Schultz announced she was leaving her DNC post after the convention.

The DNC contacted CrowdStrike when experts discovered the hacking.

CrowdStrike said one group, dubbed Cozy Bear, gained access last summer and was monitoring the DNC's email and chat communications. The other group, nicknamed Fancy Bear, targeted opposition research files in late April.

Fancy Bear allegedly works for the GRU, or Russia's military intelligence service, Dmitri Alperovitch, CrowdStrike co-founder and chief technology officer, told The Washington Post. Cozy Bear possibly works for the Federal Security Service, the country's security agency, which used to be led by Putin.

Putin spokesman Dmitry Peskov referred to a previous statement denying his government's involvement in the hacking.

"I absolutely rule out the possibility that the government or government agencies were involved in this," Peskov told journalists last month.

The groups also allegedly targeted the White House, the State Department and the Joint Chiefs of Staff.