Following 11 September 2001 terrorist attacks in the U.S., Uzbekistan approved the U.S. Central Command's request for access to an air base, the Karshi-Khanabad airfield, in southern Uzbekistan. However, Uzbekistan demanded that the U.S. withdraw from the airbases after the Andijan massacre and the U.S. reaction to this massacre. The last US troops left Uzbekistan in November 2005. In 2020, it was revealed that the former US base was contaminated with radioactive materials which may have resulted in unusually high cancer rates in US personnel stationed there.