Two bombs were detonated in a Sunni mosque on Friday, killing at least 15 people in the Iraqi city of Samarra, according to Al Jazeera.
The deputy head of the municipal council, Mizhar Fleih, told Al Jazeera the bombs went off during noon prayers.
"During the Friday prayer suddenly a huge explosion took place," 35-year-old Saleh al-Shamani told Reuters.
"Black smoke filled the mosque, we could not see each other. I tried to stand, but I couldn't as I had some injuries in my legs."
Many were reported injured by the bombs, which Reuters said had been hidden in the mosque's air conditioning.
Samarra, a city just north of Baghdad, is also home to a prominent Shia shrine, said Al Jazeera.
Friday's attacks come amid mounting violence in Iraq, with with more than 4,000 reported killed since April, according to the Associated Press.