Abuja - Protests by supporters of more than 200 schoolgirls kidnapped by Boko Haram have been banned in the country's capital, Abuja, police said on Monday.
Federal Capital Territory (FCT) police spokeswoman Altine Daniel confirmed the ban in a text message to AFP, saying the decision was taken "because of security reasons".
No further details were given about the exact nature of the concerns but protest organisers questioned the legitimacy of the move and eyed a possible political motive.
"There is no BASIS for and no POWER of FCT Commissioner of Police to ban peaceful assembly of any group of persons in... the city. None @ ALL," said Oby Ezekwesili on her Twitter account @obyezeks.
Noisy street protests in Abuja have become a regular feature of the campaign to keep the mass kidnapping of the girls in the public domain, as well as pressure on Nigeria's government.
The demonstrations grew out of a social media campaign #BringBackOurGirls, which attracted worldwide support from ordinary people to US First Lady Michelle Obama and Pope Francis.
Families and supporters of the missing girls were critical of Nigerian President Goodluck Jonathan's response to the abduction, accusing him of being slow to react and indifferent to their plight.
The protests have grown to involve activists and campaign groups, who have sought meetings with senior figures in Jonathan's administration, including the president himself.
But on Wednesday last week, the high-profile marches descended into violence after scores of young men attacked women protesters, throwing chairs, bottles and stones.
Some of the men were carrying posters in support of Jonathan, protest leaders said, although there was no immediate evidence connecting the gang to the head of state or his ruling Peoples Democratic Party (PDP).
Information minister Labaran Maku claimed afterwards that the majority of the protesters were members of the main opposition All Progressives Congress (APC), which is looking to unseat the PDP in next year's general election.
Banners of the smaller opposition Labour Party have been seen on previous marches, according to AFP reporters.
Ezekwesili, however, is a former education minister under former president Olusegun Obasanjo -- Jonathan's mentor -- and a former World Bank executive.