A mob set fire to a church where dozens of people had sought refuge from violence in Kenya yesterday, killing at least 50 and raising new fears that one of Africa’s most stable countries would collapse into a bloody tribal war.

The dead were mostly of the Kikuyu tribe, which overwhelmingly backed President Kibaki’s bid for a second term in last Thursday’s election. Mr Kibaki defeated his rival, Raila Odinga, by just 230,000 votes and Mr Odinga’s supporters, who are mostly ethnic Luo, believe that the election was “stolen”.

The admission last night by Samuel Kivuitu, the head of Kenya’s Electoral Commission, that he was pressured by Mr Kibaki’s Party of National Unity not to hold an inquiry into the results appeared to support the claim. European envoys and the state-run Human Rights Commission had called for an investigation.

More than 300 people have been killed in Kenya since the election, and last night there was no sign that security forces were willing, or able, to bring the rampaging mobs under control. Gangs of machete-wielding men set up roadblocks along the main road out of Nairobi to the west, pulling Kikuyus from their cars.

“We cannot move out of the house,” said Elijah Ombiru, a father of four, in Eldoret. “People are being killed everywhere.”

While calm was restored in Nairobi and among Mr Odinga’s slum strongholds, things in the west – where support for his political party is strongest – were getting worse.

The Kenyan Red Cross said that 70,000 people had fled the violence, and some Kikuyus had reportedly crossed into Uganda for safety. “This is a national disaster,” said Abbas Gullet, the agency’s secretary-general. Aerial footage taken by the Red Cross showed farms and hundreds of houses on fire and roadblocks every ten kilometres (six miles). Only those from “the right ethnic group” were allowed through the barricades, Mr Gullet said.

A police spokesman told a news conference in Nairobi: “We never expected the savagery to go so far.”

The violence has erupted throughout Kenya, from the capital’s shanty towns to coastal resorts, exposing tribal resentments that have long festered. Mr Kibaki’s Kikuyu people, the largest ethnic group, are accused of using their dominance of politics and business to the detriment of others.

In the slums, which are often divided on tribal lines, rival groups have been fighting with machetes and sticks, as police fire teargas and live rounds to keep them out of the city.

Anne Njoki, 28, had fled her home in the slums after she saw her fellow Kikuyus being attacked and their homes looted. She was camped out near a military base with her sister, three-year-old nephew and seven-year-old niece. The looters had taken their “beds, blankets, even spoons”, she said. The children had not eaten for days.

Yesterday Mr Kibaki called for a meeting of all political parties, where leaders would appeal for calm. Mr Odinga, who has also urged his supporters not to resort to violence, has said he will not meet Mr Kibaki until the President steps down.

“I am only pained by what is happening and I will say that President Kibaki represents the old leadership, that old dictatorial leadership that is on its way out of Africa,” said Mr Odinga. “He’s part of the endangered species of leadership that belongs to the museum.”

The opposition candidate has called for one million people to converge on the centre of Nairobi tomorrow and declare him the “people’s president”. The Government has declared the rally illegal, raising fears of violence between protesters and the security forces. Mr Odinga’s supporters say that they expect him to be sworn in as President tomorrow, and his supporters in the slum-town of Kibera appear ready to fight.

“We have been patient. We have lowered our tempers because we want to get directives from our leaders,” said Morris Otieno, a 45-year-old businessman in Kibera. “If they say, ‘Let us go to town,’ we will go peacefully. If the police interfere, you can expect what will happen - hell will break loose.”

The refusal of either candidate to stand down has dashed hopes that the violence would abate. “I can see the beginnings of an ethnic conflict.” Mwalimu Mati, a Nairobi-based anticorruption campaigner, said. “There’s always been this undercurrent of suspicion, but by and large the poor were just the poor living together. Now the police are ringing those places and not allowing them to leave, so it’s a slaughterhouse situation.”

The tribal enmity was by no means shared by all Kenyans. Yusuf Ibrahim, a 24-year-old from the Nubian tribe, has lived in Kibera all his life.

During a lull in the violence yesterday he stood among the ruins of looted shops and shacks. “The houses are torched, the kiosks have been torched but what have we gained?” Mr Ibrahim said. “We’ve gained nothing. Where is Mwai Kibaki, where is Raila to come here and do what’s necessary?”

Mr Kibaki, 76, who won the presidency by a landslide in 2002, ending Daniel Moi’s 24 years in power, is credited with turning the country into an East African economic powerhouse. But his anticorruption campaign is seen as a failure. The main constituency of Mr Odinga, 62, is the Kibera slum, but he has been accused of failing to do enough to help its impoverished people in 15 years as an MP.

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