KANO, Nigeria - At least 18 persons were killed in an early Sunday morning attack in Nigeria's northwestern Kano State during a church service in the heart of Bayero University Kano, eyewitnesses and health workers reported.

Among the victims of the attack are professors Jerome Ayodele of the Chemistry Department and Andrew Leo of the Library Science Department respectably of the Bayero University Kano.

An eyewitness told Xinhua that some gunmen attacked the faithful when they were holding a service at 8:45 am local time in a lecture theater at the old site of the university.

The witness said the gunmen threw some improvised explosive devices in the lecture theater and opened fire on those who attempted to run away from the scene.

The witness said members of the Joint Military Task Force (JTF) later arrived at the scene and engaged the attackers in a gun battle.

Although University spokesperson Mustapha Zahradeen told reporters in Kano, the state capital, that the actual casualties were only seven, local health workers said rescue operators removed at least 18 dead bodies from the scene.

Zahradeen told Xinhua that the gunmen who stormed the university premises on motorcycles took everybody unawares because it had never occurred to them that such an attack could happen.

According to him, many students and other worshipers were critically injured and taken to the Mallam Aminu Kano teaching hospital, where there is heavy presence of security personnel guiding the entire place.

On a separate occasion, state police spokesperson Magaji Majiya said seven persons died and many others injured in a bomb attack on worshipers at Bayero University, Kano, on Sunday morning.

Majiya told Xinhua that the injured were taken to Aminu Kano Teaching Hospital.