Balloons fall over delegates and attendees at the end of the fourth day of the Democratic National Convention. (Photo by Drew Angerer/Getty Images)

The Democratic Congressional Campaign Committee, the political arm for House Dems, confirmed this morning that it has been hacked.

“The DCCC can confirm that we have been the target of a cybersecurity incident. Upon discovering the issue, we immediately took action and engaged with CrowdStrike, a leading forensic investigator, to assist us in addressing this incident,” DCCC spokesperson Meredith Kelly said in a statement. “The investigation is ongoing.”

This comes after Wikileaks, an organization that publishes secret documents, released about 20,000 emails from the Democratic National Committee right before the convention, following reports in June that the DNC’s system had been compromised for months.

The legitimacy of the emails between DNC staffers has never been in question. They reveal an organization that favored Democratic nominee Hillary Clinton over her primary opponent, Bernie Sanders, confirming the suspicions of the Vermont senator’s campaign. The back-and-forths mocked the Sanders campaign, tried to hide details of a fundraising deal with the Clinton campaign, and showed that the White House spiked an Ariana Grande performance over a donut-licking scandal, among other revelations.

The documents also have donors’ unredacted personal information, including credit card and Social Security numbers. The release led to the resignation of former DNC chair Debbie Wasserman-Schultz, a congresswoman from Florida, and a “deep and sincere apology” to Sanders and his supporters from the organization.

The Clinton campaign has linked the hack to Russia, alleging that the Kremlin is trying to influence the 2016 election and get her opponent in the White House.

Clinton’s campaign chair, John Podesta made similar claims to Reuters about the DCCC cyberattack. “I have concerns that an agency of foreign intelligence is hacking and interfering with a U.S. election,” Podesta told Reuters, adding he had not seen news of the DCCC attack.

For his part, Republican nominee Donald Trump called for more hacks.

If Russia or any other country or person has Hillary Clinton’s 33,000 illegally deleted emails, perhaps they should share them with the FBI!

— Donald J. Trump (@realDonaldTrump) July 27, 2016

He later said that he was being “sarcastic.” The Kremlin has denied any involvement in the release of the documents. Wikileaks and Assange have been mum about the source of the documents. The Federal Bureau of Investigations is investigating the incident.

And the potential for further leaks and October surprises lingers: in addition to the DNC and DCCC’s cybersecurity woes, the Clinton Foundation has also reportedly been breached. Assange told CNN that he has “a lot more material” to release.

This story has been updated.