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Russian border troops were stationed along the TajikAfghan border until summer 2005. Since the September 11, 2001 attacks, French troops have been stationed at the Dushanbe Airport in support of air operations of NATO's International Security Assistance Force in Afghanistan. United States Army and Marine Corps personnel periodically visit Tajikistan to conduct joint training missions of up to several weeks duration. The Government of India rebuilt the Ayni Air Base, a military airport located 15 km southwest of Dushanbe, at a cost of $70 million, completing the repairs in September 2010. It is now the main base of the Tajikistan air force. There have been talks with Russia concerning use of the Ayni facility, and Russia continues to maintain a large base on the outskirts of Dushanbe.

Why do US troops visit Tajikistan every so often?
to conduct joint training missions of up to several weeks duration.