Sadar is a battle-hardened commander, who gained prominence among Taliban foot soldiers following the movement's overthrow in 2001. The two officials both spoke on condition of anonymity because they were not authorised to speak publicly for the Taliban.
Sadar's appointment coincides with an uptick in Taliban attacks against Afghanistan's security forces. The US has sent additional troops to southern Helmand province, where its capital Lashkar Gah is under pressure. The provincial council head Kareem Atal earlier said roughly 80 percent of Helmand is already under Taliban control.
So far this month Taliban fighters have attacked Afghan security forces in northern Kunduz province, briefly taking control of a district headquarters. The militants also overran a district in northern Baghlan province and in eastern Paktia province. Meanwhile, in eastern Nangarhar province, Taliban militants are fighting pitched battles with security forces. Afghanistan's Ministry of Defense says its security forces are waging operations in 15 provinces.