Gunmen set off three bombs and opened fire on worshipers Friday at the main mosque in north Nigeria’s biggest city, Kano, killing at least 81 people in an attack that bore the hallmarks of Islamist Boko Haram militants, officials and witnesses said. No group, however, has taken credit for the attack.

Blasts from the coordinated assault rang out as scores of people packed into the ancient building’s courtyard for afternoon prayers.

“These people have bombed the mosque. I am face to face with people screaming,” said local reporter Chijjani Usman.

Reuters visited two mortuaries, one with 20 bodies from the attack, the other with 61, according to medical officer Muhammad Ali. The victims had gunshot and blast wounds, he said.

President Goodluck Jonathan said in statement that he would not “leave any stone unturned until all agents of terror undermining the right of every citizen to life and dignity are tracked down and brought to justice.”

Security personnel inspect the wreckage of a car believed to be used in the Kano Central Mosque bombing Friday. Gunmen set off three bombs and opened fire on worshippers at the central mosque in north Nigeria's biggest city Kano, killing at least 81. (Stringer/Reuters)

The mosque is next to the palace of the emir of Kano, the second-highest Islamic authority in Africa’s most populous country and a vocal critic of Boko Haram. The emir, former central bank governor Lamido Sanusi, was not present at the time of the attack.

“After multiple explosions, they also opened fire. I cannot tell you the casualties because we all ran away,” a member of the palace staff told Reuters on Friday.

The old mosque and palace date back centuries to when Kano was one of several Islamic empires thriving off trade in gold, ivory and spices from caravan routes connecting Africa’s interior with its Mediterranean coast. Those were the glory days of Saharan Islam that Boko Haram, a Sunni jihadist movement that is fighting to revive a medieval Islamic caliphate in northern Nigeria, says it wants to re-create.

Boko Haram disdains the traditional Islamic religious authorities in Nigeria. It has attacked mosques that do not follow its radical ideology in a bloody, nearly six-year campaign that has also targeted churches, schools, police stations, military bases and government buildings.

The insurgency has forced more than a million people to flee during its campaign focused on Nigeria’s northeast, Red Cross officials told reporters Friday.

Islamic leaders sometimes shy away from direct criticism of Boko Haram for fear of reprisals, but Sanusi, the Kano emir, angered by the kidnapping of 200 schoolgirls from the village of Chibok in April, has become an increasingly vocal critic. During a broadcast recitation of the Koran he was reported to have said:

“These people, when they attack towns, they kill boys and enslave girls. People must stand resolute. . . . They should acquire what they can to defend themselves. People must not wait for soldiers to protect them.”

— Reuters