WASHINGTON ( CNN ) -- China has refused nine U.S. Navy ships and one Air Force jet entry to Hong Kong in the past month , U.S. military officials said Friday . China has refused the USS Reuben James , seen in a 1989 photo , a Christmas port call in Hong Kong . Senior Navy officials said that Beijing denied permission for the USS Reuben James , a Navy frigate , to make a holiday port call for sailors at the end of December . The rejection occurred last week , at the same time China refused to allow the USS Kitty Hawk aircraft carrier battle group into Hong Kong for a Thanksgiving holiday port call . A U.S. Air Force C-17 flight that had been scheduled for a routine resupply of the U.S. Consulate in Hong Kong also was denied permission to enter , Navy officials said . The Kitty Hawk battle group was eventually granted permission to enter , but by then the ships were well on their way to port in Japan . Days earlier , China refused to give two U.S. Navy minesweepers safe harbor in Hong Kong during a storm on the high seas . The United States has filed a formal protest with China over the decisions . U.S. officials are baffled about the reason or reasons for the port call refusals . China recently has expressed concerns about U.S. arms sales to Taiwan and President Bush 's October presentation of a Congressional Gold Medal to the Dalai Lama , the exiled Tibetan spiritual leader . Watch China put the blame on the U.S. » . There is speculation that the Chinese may have been conducting military exercises that they did n't want the U.S. Navy to see . Others think the refusals may have been the result of a misunderstanding . Officials could not explain why the rejection of the Reuben James had not been disclosed before , even though reporters had repeatedly asked if there were any other pending port calls . One senior Navy official expressed dismay that the information had not been made public by the Pentagon . White House deputy spokesman Scott Stanzel told reporters the White House is `` aware '' of the latest refusals and referred reporters to the Pentagon . Stanzel said a `` clarification '' on the matter was being sought from Beijing . White House and other Bush administration officials have sought to defuse tensions with China , saying the United States wants to move ahead on broader issues of military cooperation . Navy officials , meanwhile , say Japan is tightening approvals for Chinese navy visits into its ports . Crew members from a Chinese ship making a port call in Japan may not be allowed to tour a Japanese Aegis warship . The U.S.-designed Aegis weapons system enables coordinated operations against threats from aircraft and missiles , surface ships and submarines . It is not clear if the Japanese decision was made at the request of the United States . E-mail to a friend .
NEW : China would n't let U.S. Air Force jet land to resupply Hong Kong consulate . Frigate USS Reuben James not allowed to enter Hong Kong for port call . China last week refused port call for USS Kitty Hawk battle group . Two U.S. minesweepers denied safe harbor during storm .