A suicide bomber struck a crowd of worshippers at a mosque in Kabul on Tuesday, killing at least 58 people in the deadliest of two attacks — the first major sectarian assaults since the fall of the Taliban a decade ago. Four other people were killed in the northern city of Mazar-i-Sharif when a bomb strapped to a bicycle exploded as a convoy of Afghanis was driving down the road, shouting slogans for the festival known as Ashoura. Health Ministry spokesman Sakhi Kargar gave the death toll and said 21 people also were wounded in that attack. The Kabul bomber blew himself up in the midst of a crowd of men, women and children. The building, which is near the presidential palace, was packed with worshippers and dozens more were crammed into the courtyard. One witness said the bomber was at the end of a line and detonated his explosives near one of the gates to the building. Sayed Kabir Amiri, who is in charge of Kabul hospitals said 54 were killed and more than 160 wounded in the blast. He said casualties were taken to several hospitals and the toll could rise. No group claimed responsibility for Tuesday's blasts, reminiscent of the wave of sectarian attacks that shook Iraq during the height of the war there. The Taliban condemned the attacks and said in a statement to news organizations that they deeply regretted that innocent Afghans were killed and wounded.