At least one person was killed on Monday as the police and members of the Islamic Movement in Nigeria (IMN), also known as Shiites, clashed again in Abuja.
A Channels Television reporter was also hit by a stray bullet.
The Shiites also set a sub-station of the National Emergency Management Agency (NEMA) at the federal secretariat, Abuja, on fire, after the police disrupted their protest.
Property worth about N200 million was said to have been lost in the clash with two vehicles of the agency also set on fire.
Reports are suggesting that the number of deaths in the clash could be as many as six.
The protest, which began from NITEL junction at Wuse 2, was disrupted by armed policemen who have cordoned the road leading to the National Assembly and three arms zone.
The group is protesting the refusal of the Federal Government to release its leader, Ibrahim El Zakzaky, and his wife, who have been in detention since 2015.
Shiites and the police had first clashed on July 9 after they gained entrance into the premises of the National Assembly.