The 600-megabyte data dump revealed at a London cybersecurity conference included spreadsheets that appeared to show DNC donors' personal information, Politico reported.

Officials at the DNC, the party's electoral strategy organization, said they were aware of more documents "stolen by Russian agents."

"The DNC is the victim of a crime — an illegal cyber-attack by Russian state-sponsored agents who seek to harm the Democratic Party and progressive groups in an effort to influence the presidential election," Interim DNC Chair Donna Brazile said in a statement.

"There's one person who stands to benefit from these criminal acts, and that's Donald Trump," she added. "Not only has Trump embraced Putin, he publicly encouraged further Russian espionage to help his campaign."

Brazile said the DNC's lawyers are reviewing the documents and suggested some of the ones that were released could have been "forged."