Lagos, Nigeria (CNN) Several people including a police officer were killed in clashes between Shiite protesters and the police in Nigeria's capital Abuja on Monday, police and a Shiite cleric told CNN.

Police fired tear gas and opened fire on members of the Islamic Movement of Nigeria (IMN) as they marched in the city, the group's spokesman Abubakar Abdulrahman said.

"The police threw two canisters at us and immediately followed it by shooting at our members. We have recovered six bodies, and many of our members are injured," Abdulrahman told CNN. CNN has not independently confirmed those deaths.

A deputy commissioner of police was shot dead by heavily armed protesters, according to the Nigeria police, and 54 people were arrested in connection to the incident. A police spokesman did not respond to questions about the force's alleged use of live ammunition.

One journalist hit by a stray bullet while covering the protest also died at the hospital, confirmed his employer, local TV station Channels Television, on Monday evening.