Kenyan police and supporters of defeated opposition leader Raila Odinga fought running battles on Friday along the main road to Nairobi's international airport.
Police used bullets, tear gas and water cannon on Friday on a large crowd of supporters of Odinga who gathered to welcome him from a trip overseas.
Odinga had been speaking in the United States and Britain about Kenya's political turmoil following a court-nullified presidential election and the fresh vote last month.
Odinga, whose claim of electoral fraud led the Supreme Court to nullify President Uhuru Kenyatta's re-election in August, boycotted the new vote, saying reforms had not been made. Kenyatta won a second, five-year term with 98 percent of the vote in the repeat election after Odinga boycotted the contest. Only 39 percent of registered voters took part.
Kenyatta's win last month is being challenged at the Supreme Court by activists and a politician amid claims of irregularities. The court will make a decision on Monday when judges could order a fresh vote or clear the way for the incumbent to be sworn in for his second term. If the election is upheld, Kenyatta will be sworn in on November 28.
Through the cordon
A police cordon-ringed a park in Nairobi where Odinga was expected to address supporters. Police used tear gas on people walking in groups toward Uhuru Park.
Youth who accused police of stopping them on Mombasa Road from going to the airport to greet Odinga threw stones at officers. People threw up burning barricades on Mombasa Road, the highway that links Nairobi's downtown business district and the airport.
Despite a partial police ban on protests in the capital and police efforts, demonstrators had gathered in the morning near the airport to wait for Odinga's return. Police checked vehicles headed from the city centre to the airport in another attempt to stop the demonstration from building up.
Kenyan TV channels broadcast footage of what they said was Odinga's motorcade leaving the airport after he landed just before midday. Motorcycle taxi drivers and people on foot shouted their support as the motorcade moved toward downtown.
Rights activists condemned the police actions, accusing officers of taking sides in the political crisis and violating the constitution by preventing opposition supporters from assembling.
The nullification of Kenya's August election was the first time a court in Africa had overturned a presidential vote.
At least 70 people have died in political unrest since then, the majority opposition demonstrators shot by police during protests.
"In the face of this shameful police brutality and serious violations of human rights to life and physical security, the Uhuru Kenyatta government has remained mute and at times cheered the police on and made alarming statements in support of horrifying police actions," rights activist Ndungu Wainaina said.