White House national security adviser Robert O'Brien said Sunday that Secretary of State Mike Pompeo will not run for a Senate seat in Kansas.

O'Brien said on ABC's "This Week" that Pompeo told him that he plans to stay on as the secretary of State.

"I suspect Secretary Pompeo will stay," O'Brien said. "I spoke with him about this two nights ago. He said he's not running for Senate. He said he's staying as secretary of State."

The White House adviser told ABC's Jon Karl that he enjoys working with Pompeo and hopes he doesn't leave, calling him a "fantastic secretary of State."

"He was one of the president's best picks for the cabinet," he said.

Rumors have circulated about whether Pompeo would run for a Kansas Senate seat in 2020, with Republican lawmakers encouraging the move. Former Kansas Secretary of State Kris Kobach (R) leads the GOP primary unless Pompeo enters.

Pompeo has repeatedly denied plans for a Senate run. But President Trump has lauded a potential Pompeo run, saying he would "win in a landslide" if he jumped into the race.