Outgoing United States Defense Secretary Chuck Hagel said Thursday that he and President Barack Obama had “no major differences” that led to Hagel’s resignation, The Associated Press (AP) reported.

Hagel said he simply came to the conclusion that it was the right time for him to step aside, and he leaves believing that he accomplished a great deal.

The comments marked the first time Hagel has responded to questions about his resignation since he submitted it November 24.

Asked directly whether he felt he was pressured to resign, Hagel was not specific. He called it a “mutual decision” with Obama based on one-on-one talks at the White House. He said there was no single reason for his resignation.

After Hagel’s resignation, officials privately said he was forced out after losing the confidence of the White House, as the United States wages an air war against Islamic State jihadists in Iraq and Syria.

On Thursday Hagel said that he and Obama had talked about the coming two years, the last of Obama’s term, and saw what Hagel called “another zone” of challenges ahead for the country. “Leaders have to be wise enough to know that,” he said.

“We both came to the conclusion,” he said, referring to his private consultations with Obama, “that I think the country was best served with new leadership. He thought it was (also), over at this institution after we had talked through it.”

When Obama announced that Hagel was leaving, he called the former Republican senator from Nebraska an “exemplary” Pentagon chief and indicated that resigning was Hagel’s decision.

He said Hagel approached him and “determined that … it was an appropriate time for him to complete his service.”

The White House says it will announce Hagel’s replacement Friday. Earlier this week it was reported that Obama was poised to nominate the former number-two ranking official at the Pentagon, Ashton Carter, as Hagel’s replacement.