Jimmy Carter said he doesn’t believe President Trump won the 2016 election legitimately.

Speaking at a Carter Center conference on human rights on Friday, the former president said a full investigation into Russian interference “would show that Trump didn’t actually win the election in 2016.”

“He lost the election and he was put into office because the Russians interfered on his behalf,” Carter said.

When asked if that meant Trump was an illegitimate president, Carter said, “Based on what I said, which I can’t retract.”

Earlier this week, Carter praised the president’s handling of escalating tensions with Iran. He has previously offered to help Trump with denuclearization talks with North Korea.