Afghanistan has laid the foundation for a stable and independent government, but much work remains to be done, Afghan President Hamid Karzai said after receiving an honorary doctorate of letters at the University of Nebraska at Omaha. "My plea today, through this university ... to the rest of the world, is to remain with Afghanistan, to be steady and friendly with Afghanistan, until Afghanistan is able to stand on its own feet," Karzai said Wednesday. Improvements are being made, Karzai said, with presidential elections held in October and parliamentary elections scheduled to take place in three months. Given a key to the city of Omaha, Karzai said he hoped to establish a sister-city relationship between Omaha and Kabul, the Afghan capital. Karzai credited Thomas Gouttierre, director of the university's Center for Afghanistan Studies, for maintaining ties with Afghanistan that date to the 1970s. The center has provided educational materials for Afghan children, among other projects. The university ceremony ended a daylong sojourn to Nebraska that included a visit to a northeastern Nebraska cattle farm and a trip to Offutt Air Force Base, where Karzai thanked U.S. troops. "Your work, your service and your sacrifice has brought back Afghanistan to the Afghan people," Karzai told the mostly military crowd of about 350 gathered at the air base. After the stop at Offutt, Karzai toured the feed yard and farm of Harry Knobbe, in West Point in northeast Nebraska. This week Karzai and President George W. Bush. Bush signed a strategic partnership agreement that ensures long-term U.S. support for Afghanistan in economic, security and other sectors.