Abuja - Scores of young men armed with bottles and stones on Wednesday attacked women protesters staging a demonstration over the plight of Nigerian schoolgirls kidnapped by Boko Haram, an activist said.
Hadiza Bala Usman, a leader of the Bring Back Our Girls Movement, told AFP that the men beat some of the protesters with chairs and bottles.
"We were attacked by a group of hooligans," she said. "Some of them attacked our heads with chairs."
An AFP cameraman covering the protest said his tripod was destroyed by the group, which appeared intent on blocking the demonstration.
Photos of smashed plastic chairs from the demonstration were posted on Twitter.
Some of the men were carrying posters in support of President Goodluck Jonathan, Usman said, but there was no immediate evidence connecting them to the Nigerian leader or the ruling party.
Some groups have claimed that the kidnapping crisis has been sensationalised to embarass Jonathan.
Usman also accused the police of watching the violence unfold but doing nothing.
"We are women. How could the police just watch and do nothing?" she said.
"They came to tell us that we should move away because more hooligans were coming. How can a Nigerian policeman tell us they cannot protect us?"
The Bring Back Our Girls movement has held rallies in Abuja and other Nigerian cities demanding the release of more than 200 schoolgirls who were kidnapped on April 14 in Chibok, northeastern Borno state.
Since Monday, some groups opposing the rallies have assembled at the main protest site but there had been no previous reports of violence.
"We wrote to the inspector general of police about this problem," Usman told AFP, adding that the protesters had received assurances that they would be protected.
"We refuse to be intimidated," she said, insisting that despite the violence, the rallies would continue.