At least three Senators have placed procedural holds on the confirmation of Frank Kendall to become Air Force secretary, Politico Morning Defense reported.

Sen. Elizabeth Warren (D-Mass.) wants more pledges from Kendall that he will not be swayed by his past work for defense contractors. Sen. Gary Peters (D-Mich.) placed a hold protesting the Air Force’s decision not to place a new F-35 training center at Selfridge Air National Guard Base, Michigan.

Sen. Mike Lee (R-Utah) has also placed a hold on Kendall’s confirmation, which has already cleared the Senate Armed Services Committee.

DOD photo by Master Sgt. Adrian Cadiz