U.S. President Barack Obama announced Monday that Defense Secretary Chuck Hagel will step down from his position as soon as the Senate confirms a successor.

    Hagel, who has served as Defense secretary since February 2013, was forced out by Obama, U.S. media said.

    During his remarks from the White House, however, Obama praised Hagel as an “exemplary” defense secretary, calling him critical to a number of national security accomplishments during his tenure, and characterized Hagel’s resignation as his own choice.

    However, Arizona Sen. John McCain, the expected incoming chairman of the Armed Services Committee, said on local Arizona radio station KFYI 550’s “The Mike Broomhead Show” that he spoke with Hagel last week and the Defense secretary was “frustrated.”

    Throughout the day Monday, administration officials continued to insist the decision for Hagel to step down was mutual and had nothing to do with his feelings on the administration’s defense strategy.

    Pentagon Press Secretary John Kirby told CNN’s Christiane Amanpour that “the secretary’s decision to resign has nothing to do with Iraq policy or strategy.”

    “He’s very much a strong advocate for the policy and the strategy that we’re executing there,” he said.

    He added that Hagel’s resignation doesn’t hint at any “major changes” to the nation’s strategy in Iraq.

    Behind the scenes, administration officials told CNN there were a series of discussions over the past several weeks with the president, initiated by Hagel. The talks covered a “broader discussion of national security for the next two years,” a defense official said.

    The two came to realize that “a different focus was needed and a change is in order,” the official added. “It is wrong to conclude that this was a protest by Hagel or it was over policy differences.”

    The New York Times first reported Monday morning that Obama asked Hagel to step down last Friday, seeking to reassure critics of the president’s foreign policy with the move.

    The move, White House officials told the Times, was meant to acknowledge that the new national security threats facing the nation — most notably the rise of the Islamic State in Iraq and Syria — call for a different kind of leadership in the Defense Department.

    Obama did not announce a successor Monday. According to a White House aide, the list to replace Hagel includes former Under Secretary of Defense for Policy Michele Flournoy and former Deputy Secretary of Defense Ash Carter.

    (SD-Agencies)