A witness told AFP news agency the attackers had first thrown in explosives and fired shots, “causing a stampede among worshippers”.
“They now pursued them, shooting them with guns. They also attacked another service at the sporting complex.”
Another witness spoke of “pandemonium”, and said he had seen two men shooting indiscriminately.
Mohammed Suleiman, a History lecturer at the University, said security guards had to run for their lives when the violence broke out.