More than 20 people were injured and a similar number arrested when a banned political-religious group clashed with police in the Kenyan capital.
Hundreds of members of Mungiki, a militant group that frequently hits the headlines in Kenya, tried to demonstrate to demand that their organisation be legalised, but police moved in to disperse them, sparking the fighting.
Police said that more than 20 of the demonstrators suffered injuries, including one who was shot in the arm as police fired in the air to disperse the crowd that had gathered in central Nairobi shouting slogans in praise of Mungiki.
The demonstrators threw stones at the police, who charged at the group firing in the air and beating them with batons.
"At least 20 people were arrested as police and young members of Mungiki engaged in running battles for the better part of the morning," a senior police officer told AFP.
"At least one person was shot in the right arm," said the officer, adding that the person was hit by a stray bullet.
Members of the Mungiki group carried banners calling for the lifting of the ban against their group, which has been outlawed because of frequently engaging in violence.
The Mungiki demonstrators had taken advantage of a meeting convened by a group of Mau Mau freedom fighters, who spearheaded Kenya's independence movement in the 1950s.
Dozens of Mau Mau members had gathered in Nairobi to thank the government for lifting a colonial-era ban on the organisation, but Mungiki joined them and tried to march in the streets.
In July, National Security Minister Chris Murungaru lifted the ban on Mau Mau, allowing the group to organise public meetings and register as a society.