KABUL—Taliban insurgents have seized most of Herat, Afghanistan’s third-largest city, and also captured Ismail Khan, the veteran local commander leading militia resistance there, local officials said on Friday. The fall of Herat, the latest in a series of major provincial cities to be taken by the Taliban in the past few days, has dealt a shocking blow to the government of President Ashraf Ghani only weeks after the withdrawal of U.S. forces. One official said Afghan government forces had agreed to withdraw from Herat airport, 15 km (nine miles) from the city, and the Army Corps commander’s headquarters, the last centers under their control. However other sources said Afghan forces were still at the airport as of 1 p.m. local time (0830 GMT). “The Taliban agreed that they will not pose any threat or harm to the government officials who surrendered,” said provincial council member Ghulam Habib Hashimi. As fighting …