A mortar attack on Tuesday marred the transition of responsibility from NATO to Afghan officials in Mehtar Lam, the second of seven areas due to be transferred this week. Two mortar shells landed close to the town’s government office in the eastern Afghan province of Laghman where senior government ministers and Afghan and foreign commanders were attending the formal handover. The transition process comes with Washington starting to lower troop numbers in Afghanistan as part of plans to recall 33,000 American troops by the end of next summer and put Afghans in charge of their country by the end of 2014.