President-elect Donald Trump ripped into Rep. John Lewis (D-Ga.) in a series of Tweets Saturday morning after the civil rights icon said he was not a "legitimate president."

"Congressman John Lewis should spend more time on fixing and helping his district, which is in horrible shape and falling apart (not to mention crime infested) rather than falsely complaining about the election results. All talk, talk, talk - no action or results. Sad!" Trump wrote in a series of tweets.

Lewis, a key civil rights leaders in the 1960s, represents Georgia's 5th congressional district, which includes three-fourths of Atlanta and many of its affluent suburbs. He told NBC's "Meet the Press" on Friday he wouldn't be attending Trump's inauguration next week and blames the Russians for helping him win.

"I believe in forgiveness. I believe in trying to work with people. It will be hard. It's going to be very difficult. I don't see this president-elect as a legitimate president," Lewis said.

"I don't plan to attend the inauguration. It will be the first one that I miss since I've been in Congress. You cannot be at home with something that you feel that is wrong, is not right."

U.S. Intelligence agencies have said Russia meddled in the election to help Trump win. After spending weeks challenging that assessment, Trump finally accepted that the Russians were behind the election-year hacking of Democrats that roiled the White House race. However, he also emphasized that "there was absolutely no effect on the outcome of the election including the fact that there was no tampering whatsoever with voting machines."

The 16-term congressman testified earlier this week against Trump's choice of Sen. Jeff Sessions to be attorney general, citing the Alabama Republican's record on ensuring minorities have the right to vote. Lewis was beaten and bloodied during the fight for civil and voting rights.

The Associated Press contributed to this report.