Gunmen in southern Pakistan kidnapped an American United Nations official and fatally shot his driver Monday, the latest in a recent series of high-profile kidnappings and targeted hits on foreigners. Pakistani police in the southern city of Quetta said an unknown number of gunmen ambushed the car of John Solecki, the chief of the U.N. refugee office in the province of Baluchistan, about 8:30 a.m., soon after he left home for his office. The car's driver, Hashim Raza, was killed almost instantly after the gunmen opened fire on the vehicle, said Khalid Masood, a senior police official in Quetta. [...] Abductions and assassinations of foreigners and aid workers have increased in Pakistan within the past year, affecting the operations of several major humanitarian organizations in the country, including the U.N. In April, Taliban gunmen kidnapped and later released two local workers with the U.N.'s World Food Program in northwest Pakistan.