The FBI is reportedly investigating a cyberattack against the Democratic Congressional Campaign Committee (DCCC), the Democratic fundraising arm of the U.S House of Representatives, Reuters reports.

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

The attack comes a week after WikiLeaks released a trove of Democratic National Committee (DNC) emails that showed the party's officials worked to sabotage Sen. Bernie Sanders' (I-Vt.) presidential campaign. The fallout from the leak forced the ouster of DNC chair Debbie Wasserman Schultz.

"The investigation is ongoing," Kelly added. "Based on the information we have to date, we've been advised by investigators that this is similar to other recent incidents, including the DNC breach."

Reuters reports:

The previously unreported incident at the Democratic Congressional Campaign Committee, or DCCC, and its potential ties to Russian hackers are likely to heighten accusations, so far unproven, that Moscow is trying to meddle in the U.S. presidential election campaign to help Republican nominee Donald Trump.

However, Director of National Intelligence James Clapper on Thursday said it was too early to say who was behind the hack.

"I don't think we're quite ready yet to make a call on attribution," he said at the Aspen Security Forum, a conference on national security in Colorado. "We all know there's just a few usual suspects out there, but in terms of the process we try to stick to, I don't think we're ready to make a public call on that yet."

Two unnamed sources told Reuters the hack may have begun as early as June.