Two bomb blasts aboard separate minibuses killed at least nine people on Thursday in Mazar-i-Sharif, police said, a week after a deadly explosion rocked a Shia mosque in the northern Afghan city. The number of violent public attacks has fallen since Taliban Islamists seized control of Afghanistan last August after 20 years out of power, but the Sunni extremist Islamic State group has continued to target Shia Muslims, who they view as heretics. Thursday’s blasts occurred within minutes of each other in different districts of Mazar-i-Sharif as commuters were heading home to break their dawn to d…