At least four people were killed in the capital following clashes between security forces and members of the Islamic Movement of Nigeria, according to the Shia group.
Demonstrators again took to the streets of Abuja on Monday demanding the release of their leader Ibrahim el-Zakzaky- in detention since 2015 – following reports of worsening health conditions of their leader and his wife who is also being held.
Mahdi Garba, a member of the Shia movement, told Al Jazeera that Mondays protest started peacefully with supporters chanting “Free Zakzaky” but their members were attacked by the police.
“The total number of casualties is yet to be ascertained but for now four persons confirmed dead and many injured,” Garba said.
Another eyewitness said police fired live ammunition and tear gas canisters at the protesters in an area that houses the parliament building, executive, and judicial arm.
“Shots were fired as I came out of a building in the central area, which was packed with civil servants during their lunch break,” Fakhuus Hashim, who witnessed the clashes, told Al Jazeera.
“Everyone started running and more shots were fired. They [protesters] burned the fire service station beside the ministry of foreign affairs,” he added.
No immediate response was available from Nigerias police.
An analyst suggested on Monday the security crackdown was unlikely to deter the group from taking to the streets.
“Bullets will not stop them. They will not stop until their leader is released. In fact, more violence from the state will create radicals and further make mediation difficult,” Abdullahi Murtala, a security analyst with the Abuja-based Goro Initiative, told Al Jazeera.
Murtala said the deteriorating health of the groups leader is fuelling resolve and amplifying their frustration.
“Have you seen the protesters? Young men and women driven by ideology and willing to die for the cause,” he said.
The demonstration is a continuation of a series of protests launched by the Islamic Movement of Nigeria (IMN) that resulted in bloody clashes with Nigerian police.
Several people were killed and more than 40 members of the organisation were arrested last week after the National Assembly building was closed and gunshots fired during a demonstration. Each side blamed the other for the gunfire.
The group that represents Nigerias minority Shia Muslims said it will continue protesting until they secure the release of el-Zakzaky, an Islamic scholar who founded the IMN in the early 1980s.
Garba Shehu, a presidential spokesman, said in a series of tweets recently that President Muhammadu Buhari “will not ask the countrys judiciary to abandon due process and set a suspect free”.
Shehu accused the protesters of “openly insulting the president and other leaders”.
El-Zakzaky was incarcerated by successive military governments. A number of court orders instructing the current government to release the couple have gone unheeded.
A presidential spokesman has told the press the IMN leader was being kept in custody “for his own safety”.
For more than three decades, the Shia Muslim group has had regular run-ins with security forces in Nigeria while demonstrating against perceived religious persecution.
About 400 members of the group have been killed by police in response to largely peaceful protests since 2015, according to human rights groups.