U.S. President Donald Trump told Israeli Prime Minister Benjamin Netanyahu in December that Washington would back Israeli strikes targeting Iran’s ballistic missile program if diplomatic efforts with Tehran fail, according to U.S. media.

Discussions in Washington have shifted away from whether Israel could strike, moving instead toward how the U.S. might facilitate such a mission through technical and diplomatic means, said multiple people familiar with the matter, according to a CBS News report.

Key elements of this proposed cooperation include aerial refueling for Israeli aircraft to extend their operational range and the complex task of securing overflight permissions from neighboring sovereign nations.

Jordan, Saudi Arabia, and the United Arab Emirates have said they would not permit their airspace for strikes on Iran.

The report emerged as Washington significantly steps up its military presence in the region, deploying the USS Abraham Lincoln carrier strike group with plans to send the USS Gerald R. Ford aircraft carrier as well.

A second round of negotiations between Iranian and American delegations is scheduled for Tuesday in Geneva, with Omani representatives serving as mediators.

Secretary of State Marco Rubio said Sunday that Trump “prefers diplomacy” on Iran, adding that U.S. envoys Steve Witkoff and Jared Kushner are traveling for “important meetings.”

“We’ll see how that comes out,” Rubio added.