President Donald Trump has issued a full pardon to I. Lewis "Scooter" Libby, a former top aide to Vice President Dick Cheney.

White House spokeswoman Sarah Huckabee Sanders says in a statement Friday that Trump has issued the pardon.

Libby is Cheney's former chief of staff. He was convicted of lying to investigators and obstruction of justice following the 2003 leak of the identity of CIA operative Valerie Plame.

President George W. Bush later commuted Libby's 30-month prison sentence, but didn't issue a pardon despite intense pressure from Cheney. No one was ever charged with the leak.

Trump says in the statement that he does not know Libby, but "for years I have heard that he has been treated unfairly. Hopefully, this full pardon will help rectify a very sad portion of his life."

The process to pardon Libby began when Reince Priebus was chief of staff, but it was stalled in the White House counsel's office. It was revived recently by former U.S. attorney Joseph diGenova, who assists Trump's legal team but did not formally join it, and his wife and law partner Victoria Toensing. 

Some fear Trump's pardoning of Libby could be seen through the lens of the ongoing special counsel investigation into Russian election meddling and any ties to the Trump campaign. Multiple associates of Trump's campaign, including Paul Manafort, Michael Flynn, Rick Gates and George Papadopoulos, have been charged in connection to that probe, which Trump has repeatedly called a "witch hunt."

Trump has already pardoned another controversial conservative, former Arizona Sheriff Joe Arpaio, who was convicted of defying a judge's order. 

(The Associated Press, CBS News contributed to this report.)