WASHINGTON (Reuters) – Russian government hackers penetrated the computer network of the Democratic National Committee and gained access to the entire database of opposition research on Republican presidential candidate Donald Trump, the Washington Post reported on Tuesday.

“The intruders so thoroughly compromised the DNC’s system they also were able to read all e-mail and chat traffic,” the paper said, citing committee officials and security experts.

Representative Debbie Wasserman Schultz, chairwoman of the Democratic National Committee, confirmed the breach.

“When we discovered the intrusion, we treated this like the serious incident it is …,” Wasserman Schultz said in a statement. “Our team moved as quickly as possible to kick out the intruders and secure our network.”

The Post quoted U.S. officials as saying Russian spies also targeted the networks of Trump and Democratic presidential candidate Hillary Clinton, as well as computers of some Republican political action committees.

It said some of the hackers had access to the Democratic National Committee network for about a year “but all were expelled over the past weekend in a major computer clean-up campaign.”

(Reporting by Susan Heavey; Writing by Mohammad Zargham; Editing by James Dalgleish)