The Federal Bureau of Investigation has launched a probe into the hacking of the Democratic National Committee's emails, 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 agency 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."

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The publication of the approximately 20,000 emails showed a DNC favorable to Hillary Clinton over Bernie Sanders, leading Chairwoman Debbie Wasserman Schultz to announce her resignation on Sunday, effective at the end of the party's convention this week.

The Clinton campaign suggested on Sunday that Russia had played a role in the affair, with campaign manager Robby Mook saying that the Kremlin is trying to help Donald Trump. On Monday, Mook pointed to reporting by The New York Times citing researchers who have concluded that two Russian intelligence agencies had breached the party's servers.

Trump mocked the notion 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"