China is mounting a serious effort to challenge U.S. military superiority in air and space, forcing the Pentagon to seek new technologies and systems to stay ahead of its rapidly developing rival, Deputy Defense Secretary Robert Work said Monday.

The Pentagon's chief operating officer, speaking to a group of military and civilian aerospace experts, said China was "quickly closing the technological gaps," developing radar-evading aircraft, advanced reconnaissance planes, sophisticated missiles and top-notch electronic warfare equipment.

While hoping for a constructive relationship with China, the Pentagon "cannot overlook the competitive aspects of our relationship, especially in the realm of military capabilities, an area in which China continues to improve at a very impressive rate," he said.