Police opened fire on protesters escorting Raila Odinga, Kenya's opposition leader, from Nairobi's international airport yesterday, killing at least five people in an ominous escalation of the country's political crisis.
For the first time since protests erupted more than three months ago, serious violence erupted in the affluent centre of the Kenyan capital as police attempted to prevent Mr Odinga from addressing a rally called at a city park.
The car carrying Mr Odinga, who was returning from a trip to the United States and Britain, was struck by a tear-gas canister that splintered its bullet-proof windscreen, an incident that goaded his supporters into further fury.
Helmeted police used tear gas, water cannon and live fire to disperse stone-throwing protesters during repeated clashes along streets which the opposition motorcade passed. There was also violence in other parts of the city.
Although at least 66 people have been killed since Mr Odinga challenged his defeat in a presidential election in August, this is the first time that the opposition leader has been directly caught up in such extreme unrest.
A police decision to ban his homecoming rally, also a first, coupled with the ruthless police response, suggests that Kenya's government may be adopting a more hardline approach to the protests.
The police insisted they had not used live ammunition and were responsible for none of the deaths. Journalists and witnesses who saw three corpses said all had bullet wounds.
Senior figures in Mr Odinga's opposition, the National Super Alliance (Nasa) coalition, warned it could prove more incendiary too.
"The wanton use of force is ill-advised," Mutual Kilonzo Jr, an opposition senator, wrote on Twitter. "It will only strengthen the resolve of Nasa and its supporters."
Kenya is experiencing its worst political violence in a decade as anger simmers over two contentious presidential elections held in the past three months.
The first saw President Uhuru Kenyatta's re-election overturned by the supreme court.
The second was boycotted by Mr Odinga.