Gunmen have attacked church services on a university campus in northern Nigeria, using small explosives to draw out and gun down worshippers in an assault that killed at least 16 people, officials said.
The attackers targeted an old section of Bayero University's campus where religious groups use a theatre and other areas, according to Kano state police commissioner Ibrahim Idris, who said the assault left many others seriously wounded.
"By the time we responded, they [started] motorcycles and disappeared into the neighbourhood," he said.
After the attack, police and soldiers cordoned off the campus as gunfire echoed in the surrounding streets. Abubakar Jibril, a spokesman for Nigeria's emergency management agency, said security forces refused to allow rescuers to enter the campus. Journalists were also turned away from the university.
Andronicus Adeyemo, a Nigerian Red Cross official, said a survey of hospitals and morgues showed the attack had killed at least 16 people. A number of people suffered injuries, though the aid agency did not immediately have an exact figure, Adeyemo said.
No group immediately claimed responsibility. However, Idris said the attackers used small explosives packed inside aluminium drink cans for the assault, a method previously used by radical Islamist sect Boko Haram.
Boko Haram is waging a growing sectarian battle with Nigeria's weak central government, using suicide car bombs and assault rifles in attacks across the country's predominantly Muslim north and around its capital Abuja. Those killed have included Christians, Muslims and government officials. The sect has been blamed for more than 450 killings this year, according to an Associated Press count.
In January, a co-ordinated Boko Haram assault on government buildings and other sites in Kano killed at least 185 people. Since then the group has been blamed for attacks on police stations and other smaller targets in the city.
On Thursday, the sect carried out a suicide car bombing at the Abuja offices of the influential newspaper ThisDay and a bombing at an office building the paper shared with other publications in the city of Kaduna. At least seven people were killed in those attacks. That night, attackers also bombed a building at Gombe State University, though authorities said no one was injured.
Boko Haram has rejected efforts to begin indirect peace talks with Nigeria's government. Its demands include the introduction of strict Sharia law across the country, even in its Christian south, and the release of all imprisoned followers.
It has increasingly targeted churches, including a Christmas Day suicide bombing of a Catholic church in Madalla, near Nigeria's capital, which killed at least 44 people.