In a joint statement, Secretary of State Condoleezza Rice and Britain’s Foreign Secretary David Miliband welcomed the emergency visit and called “on all political leaders to engage in a spirit of compromise that puts the democratic interests of Kenya first”.

“The immediate priority is to combine a sustained call from Kenya’s political leaders for the cessation of violence by their followers with an intensive political and legal process that can build a united and peaceful future for Kenya,” the statement said.

The UN cited Kenyan police as saying 70,000 people had been displaced so far. Around 5,400 people have also fled to neighboring Uganda, said Musa Ecweru, that country’s disaster preparedness minister.

In Nairobi’s slums, which are often divided along tribal lines, rival groups have been fighting each other with machetes and sticks as police use tear gas and bullets to keep them from pouring into the city centre. The capital has been a ghost town for days, with residents stocking up on food and water and staying in their homes.

After a brief lull, sporadic clashes broke out again on Tuesday night in Nairobi’s sprawling Mathare slum, where fires lit the evening sky.