Taliban leader Haibatullah Akhundzada was not in the mosque near Quetta when a bomb went off but his younger brother, Hafiz Ahmadullah, was leading Friday prayers and was among four people killed, several Taliban officials have said. There was no claim of responsibility for the blast that came after both Taliban and US officials have reported progress in talks on an agreement centered on a US troop withdrawal from Afghanistan in exchange for a Taliban security guarantee.