Kano - Kaduna State where clashes between the military and Shiite Muslims led to over 300 deaths last year has banned the Islamic Movement of Nigeria (IMN), saying it was a security threat.
Two days of violence began on December 12, when supporters of the pro-Iranian cleric and IMN head, Ibrahim Zakzaky, refused to allow the chief of army staff's convoy to pass through the northern city of Zaria in Kaduna state.
In April, rights group Amnesty International accused Nigeria's military of shooting dead more than 300 Shiite Muslims, burying them in mass graves and destroying evidence of the crime.
The Kaduna state government later confirmed the Amnesty report, saying that the army used "excessive force" and that those responsible for the killings should be prosecuted.
But in a press release issued late Friday, Kaduna state governor Nasir El-Rufai said IMN was a threat to Nigeria.
"The Kaduna state government has issued an order declaring the Islamic Movement in Nigeria (IMN) an unlawful society," a statement said.
It said the term applied to "any organisation whose activities are dangerous to the security and good governance of the state."
The IMN said it would challenge the move.
"We are not surprised by this decision of the Kaduna state government to ban the IMN," spokesperson Ibrahim Musa told AFP.
"What do expect from someone that attacked you in your house, killed people in hundreds and demolished homes for no just reason?" Musa said.
"We condemn this illegal decision in the strongest terms and we will challenge this decision through all legitimate means."
IMN leader Zakzaky, who lost an eye and was left partly paralysed in the violence, has been held in custody since December.
He has previously been imprisoned for calling for an Iranian-style revolution to create an Islamic state in the country's north.
There have been fears the military action against the Shiite group in Zaria could trigger another violent uprising similar to that of Boko Haram, whose insurgency has left some 20 000 dead since 2009.