Vice Adm. Robert Harward, a former deputy commander of the U.S. Central Command, became the front-runner late Monday to replace Michael Flynn as the White House national security adviser, following lengthy discussions among top advisers to President Trump and several Cabinet members after Flynn resigned.

Harward’s rapid ascension to the top of Trump’s three-person shortlist for the position was confirmed by two White House officials who were not authorized to speak publicly.

Vice President Pence has been leading the discussions and working closely with Defense Secretary Jim Mattis, Homeland Security Security John F. Kelly, CIA director Mike Pompeo, White House senior adviser Jared Kushner, chief strategist Stephen K. Bannon and Chief of Staff Reince Priebus, the officials said.

Harward served under Mattis while he was at U.S. Central Command and remains an ally and friend of the defense secretary.

The officials said Harward, who has been under consideration as a possible undersecretary of defense for intelligence, is seen by key players around Trump as a steady pick for the post following the tumult that surrounded Flynn.

The officials also described Harward, who had a tour on the National Security Council during George W. Bush’s presidency, where he worked on counterterrorism strategy, as someone who had a high profile in security circles but a low public profile, which is part of his appeal.

On Monday night, Tommy Vietor, a former spokesman for President Barack Obama’s National Security Council, wrote on Twitter that Harward is a “very impressive (and nice) guy.”

When asked if Harward was certain to be picked, the officials offered caution and said the discussions were ongoing. But they acknowledged that a consensus for Harward was evident, with Keith Kellogg, a decorated retired Army lieutenant general, and David H. Petraeus, a former CIA director and retired general, still on the list.

Kellogg was named acting national security adviser on Monday after Trump accepted Flynn’s resignation letter.

In the ensuing hours, a series of phone calls and meetings were held, with the intent of moving quickly to replace Flynn and find agreement on the shortlist, the officials said.

According to his Navy biography, Harward is a native of Rhode Island who “grew up in a Navy family and graduated from the Tehran American High School in Iran.” He went on to the U.S. Naval Academy and a long career in the Navy, where he worked on SEAL teams and was a commander in Afghanistan and Iraq.