According to the Afghan Interior Ministry, three gunmen stormed a Shia shrine in Kabul. There are conflicting reports on the number of dead, Sputnik reported.
16 people are dead, with at least 28 injured. A number of hostages have been taken.
Earlier on Tuesday, armed suicide bombers attacked a mosque in the Afghan capital, taking hostages.
"The US Embassy in Kabul has received reports that several heavily armed suicide bombers entered Karte Sakhi Mosque (PD-3) and may have opened fire on parishioners," reads a statement from the US Embassy in Kabul.
Parishioners had gathered at the mosque ahead of the Shiite holy day of Ashura Day, mean to end a month of mourning over the death of the Prophet Muhammad's grandson. Police had warned beforehand of the possibility of an attack.