No one immediately claimed responsibility for the attack in Kabul.
The international press freedom group Reporters Without Borders has called Afghanistan one of the world’s deadliest countries for journalists.
Gunmen stormed Kabul University as it hosted a book fair attended by the Iranian ambassador to Afghanistan.
A horrific attack at a maternity hospital in Kabul has not been claimed by any group, but the U.S. said it bears all the hallmarks of Afghanistan’s IS affiliate.
A hospital in Kabul where Doctors Without Borders runs a maternity clinic was targeted by gunmen on Tuesday, Afghan officials said.
President Ashraf Ghani's comments pointed to the first hitch in implementing the fragile U.S.-Taliban peace deal.
The report found that 2,214 people have been killed, most of them Afghans, in largely U.S.-led projects to rebuild the country.
The two professors had been abducted three years ago while working at the American University in Kabul.
Militant forces set off an explosion that collapsed the eastern Afghanistan mosque's roof.
Hours later, an explosion struck near the U.S. embassy in Kabul. The violence comes as Afghanistan faces presidential elections on Sept. 28.