KABUL—Taliban insurgents captured a key district just outside the Afghan capital Kabul in central Wardak province, forcing government forces to retreat, security officials said on Tuesday. The seizure of Nerkh district comes amid intensifying violence following an announcement by the terrorist group of a three-day ceasefire in Afghanistan for the Muslim religious holiday of Eid, starting this week. Tariq Arian, an interior ministry spokesman, said government troops made a “tactical retreat” from the district center, which is a gateway to Kabul, after a heavy firefight with the Taliban. Zabihullah Mujahid, a Taliban spokesman, wrote on Twitter that they had killed and captured some members of the Afghan security forces after seizing the district. He added that they had also seized a large cache of ammunition. The Afghan government did not comment on casualties among the security forces. The Taliban have dug in in Wardak, which lies less than an hour’s …