Five people have been killed in south-eastern Nigeria after police opened fire on supporters of an activist who backs the creation of a breakaway state of Biafra, campaigners say.
An Abuja high court on Thursday ordered the release of Nnamdi Kanu, which prompted celebrations on the streets.
The police in Onitsha city said shots were fired after officers were attacked and three people were "feared dead".
Mr Kanu was arrested by the authorities in October, accused of treason.
He is the director of the banned Radio Biafra and heads the separatist Indigenous People of Biafra (IPOB) group.
Biafran secessionists fought a three-year civil war in which more than one million people lost their lives. The uprising was eventually quelled by the military in 1970.
The court order to free Mr Kanu came after Nigeria's secret police withdrew criminal charges against him. It is not clear what these were, but may have been related to running a radio station without a licence.
But he has not been released from detention as the police say they are still investigating his alleged involvement in terrorist activities.
'Officer severely injured'
The clashes in Onitsha were prompted by "overzealous police officers firing at unarmed civilians who were celebrating a court victory", IPOB co-ordinator Uchemna Madu told the BBC Hausa service.
Fifteen other people were seriously wounded, he said.
A police spokesman said the shots were fired after the protesters attacked the security forces.
"One military officer was severely injured and had his rifle damaged," Okwechuku Allie said.
Since Mr Kanu's arrest, young people, mainly from his ethnic Igbos, have been protesting in south-east Nigeria and the oil-rich Delta region.
They belong to secessionist groups like IPOB and the Movement for the Actualisation of a Sovereign State of Biafra (Massob) and feel they have been discriminated against by those in power.
The Nigerian authorities have always maintained that most of the issues the Biafra activists are complaining about are not unique to southern part of the country.