The Central Asian nation of Uzbekistan has notified the State Department that U.S. military aircraft and personnel must leave an Uzbek air base that has been an important hub for American military operations in Afghanistan, a Pentagon official said Saturday. Glenn Flood, a Pentagon spokesman, said the notice was received Friday at the U.S. Embassy in the Uzbek capital of Tashkent, AP reported. Flood said he did not know whether the Uzbeks stated a reason for evicting U.S. forces from Karshi-Khanabad air base, commonly referred to as K2. A spokesman for the U.S. Embassy confirmed that it received an Uzbek notice Friday but would not say what it contained. A base spokeswoman declined comment. The Uzbek government in recent months had tightened restriction on use of the base, including banning night flights. «We have to step back and look at our options now and see where we go from here,» Flood said. «That airfield has been very important for our operations in Afghanistan» _ humanitarian as well as military.