US officials step up rhetoric on Russia link to email hacks

Republican vice presidential candidate Mike Pence said on Sunday that evidence implicated Russia in recent email hacks tied to the Nov. 8 U.S. election, contradicting his running mate, Donald Trump, who has cast doubt on Russia's involvement.

Pence's comments came after U.S. Vice President Joe Biden said in an interview that aired on Sunday that the United States would be sending a message to Russia "at the time of our choosing" about the email attacks. Obama administration officials initially refused to say if they thought Russia was behind the attacks, before accusing Moscow for the first time earlier this month.

JULY 26

President Barack Obama said in an interview with NBC News that "anything's possible" when asked if Russia hacked into the Democratic National Committee. "What we do know is the Russians hack our systems, not just government systems, but private systems," Obama said. "But what the motives were in terms of the leaks and all that, I can't say directly, but what I do know is that Donald Trump has repeatedly expressed admiration for Vladimir Putin."

JULY 28

Director of National Intelligence James Clapper, speaking about the hack of the DNC emails, said the U.S. intelligence community was not ready to "make the call on attribution" as to who was responsible.

AUG. 15

Homeland Security Secretary Jeh Johnson offered state officials help from hacking threats or other possible election tampering, in the face of unsubstantiated allegations by Trump that the system is open to fraud.

SEPT. 7

Speaking at a conference in Washington, Clapper said that "the Russians hack our systems all the time," but he did not officially blame them for the intrusions into Democratic Party organizations.

SEPT. 20

During a live interview with the Washington Post, Clapper said Russia had a tradition of trying to interfere in elections in other countries. He added that his biggest concern was not that a foreign power would try to affect the outcome of the U.S. election but instead "cast doubt on the whole process."

OCT. 7

The U.S. government for the first time formally accused Russia of a campaign of cyber attacks against Democratic Party organizations.

"We believe, based on the scope and sensitivity of these efforts, that only Russia's senior-most officials could have authorized these activities," the Obama administration said in a statement.

OCT. 16

Biden said in an interview with NBC News that the United States would send a "proportional" response to Russia for the hacking "at the time of our choosing and under the circumstances that have the greatest impact."

(Reporting by Dustin Volz in Washington; Editing by Peter Cooney)