The Senate minority leader, Harry Reid of Nevada, asked the F.B.I. on Monday to investigate evidence suggesting that Russia may try to manipulate voting results in November. In a letter to the F.B.I. director, James B. Comey Jr., Mr. Reid wrote that the threat of Russian interference “is more extensive than is widely known and may include the intent to falsify official election results.” Recent classified briefings from senior intelligence officials, Mr. Reid said in an interview, have left him fearful that President Vladimir V. Putin’s “goal is tampering with this election.” News reports on Monday said the F.B.I. warned state election officials several weeks ago that foreign hackers had exported voter registration data from computer systems in at least one state, and had pierced the systems of a second one. The bureau did not name the states, but Yahoo News, which first reported the confidential F.B.I. warning, said they were Arizona and Illinois. Matt Roberts, a spokesman for Arizona’s secretary of state, said the F.B.I. had told state officials that Russians were behind the Arizona attack.
After the F.B.I. warning, Arizona took its voter registration database offline from June 28 to July 8 to allow for a forensic exam of its systems, Mr. Roberts said.
The F.B.I., in its notice to states, said the voter information had been “exfiltrated,” which means that it was shipped out of the state systems to another computer. But it does not mean that the data itself was tampered with.
It is unclear whether the hackers intended to affect the election or pursued the data for other purposes, like gaining personal identifying information about voters. The F.B.I. warning referred to “targeting activity” against state boards of elections, but did not discuss the intent of the hackers.