Nigeria police 'killed civilians'
Nigerian security forces killed dozens of people after they were called in to deal with sectarian riots sparked by an election last year, a lobby group says.
Human Rights Watch wants the officers involved in the violence, in the central city of Jos, to be prosecuted.
The group said officers opened fire at random and killed about 130 people, mostly young Muslim men.
Police chiefs deny the claims and some witnesses have suggested the gunmen were impersonating security officers.
Decades of resentment
The violence was ignited by rumours that a Muslim-backed party's candidate for council leader had lost a local election.
Christians burned mosques and Muslims burned churches before security forces were sent in and imposed a curfew.
"In responding to the inter-communal violence, the Nigerian police and military were implicated in more than 130 arbitrary killings, mostly of young Muslim men," said Eric Guttschuss of Human Rights Watch.
"[We] call on government authorities to promptly arrest and prosecute those responsible."
In their report, the rights group says about 700 people died in the violence - many more than has been officially acknowledged.
Mohammed Lerama, spokesman for the Plateau State police, denied the accusations.
"The police who were sent to restore peace cannot turn around again to kill the harmless civilians they were supposed to protect," he said.
Thousands have died in religious and ethnic violence in northern and central Nigeria in recent years.
However poverty and access to resources such as land often lies at the root of the violence.