The military conceded Monday that it missed at least three suspected Chinese spy balloons that passed through U.S. airspace and territory during President Donald Trump’s presidency due to a “domain awareness gap.” Air Force General Glen VanHerck, head of U.S. North American Aerospace Defense Command and Northern Command, said that those three incidents were only discovered after the fact using “additional means” for collecting intel. The Biden administration’s National Security Adviser Jake Sullivan said the U.S. enhanced its surveillance of territorial airspace after Joe Biden became president. “We enhanced our capacity to be able to detect things that the Trump administration was unable to detect,” he said. Several Republicans have taken stabs at Biden for not shooting down the balloon earlier; Biden said he wanted to shoot it down but followed the Pentagon’s advice that “we should not shoot it down over land, it was not a serious threat.”