NAIROBI (Reuters) - Up to 1,000 people may have died in more than a week of riots and post-election violence in Kenya, opposition leader Raila Odinga said on Monday.
The head of the African Union (AU), Ghanaian President John Kufuor, is due to land in Nairobi on Tuesday. Odinga said Kufuor could begin chairing talks on Wednesday.
Odinga called off nationwide protests by supporters to create a "peaceful atmosphere" for the talks while his rival President Mwai Kibaki summoned parliament to meet on Jan. 15.
The imminent arrival of the AU chief was a "major, major breakthrough" and "very significant move", Odinga told Reuters.
Odinga rejected an official government death toll of nearly 500 and said "closer to a thousand" people may have died.
The government says 486 died and 255,000 were uprooted in the turmoil that followed Kibaki's disputed re-election.
Aid workers say the toll could go much higher after one of Kenya's worst crises since independence from Britain in 1963.
Odinga had looked on course to win the Dec. 27 election until Kibaki, 76, was handed a narrow victory. Both sides alleged widespread rigging and international observers say the poll fell short of democratic standards.
The election and subsequent violence has marred Kenya's image as a bastion of stability in east Africa and threatened its economy -- the region's largest.
In her first public comments since arriving in Kenya on Friday, Washington's top diplomat for Africa said the political crisis had not shaken the United States' confidence in Kenya as a strong regional hub.
"It has actually further deepened our sense that Kenya is a strong regional partner," U.S. Assistant Secretary of State Jendayi Frazer told a news conference.
She said Kenyans had been let down by their leaders. "They have been cheated by their leadership and their institutions ... The political leaders have to stop the violence ... and they have to reform the institutions."
Odinga, who turned 63 on Monday, faces a dilemma of responding to international pressure to avoid provoking more violence while also maintaining momentum to oust Kibaki.
Kibaki's government accuses Odinga's Orange Democratic Movement (ODM) of "grandstanding" and stoking further unrest.
Fanning the controversy, the Law Society of Kenya accused electoral officials of "dishonesty and ineptitude", called Kibaki's swearing-in "null and void", and urged a fresh vote.
"Honourable Kibaki lacks legitimacy to govern and this is the cause of the problems that we are facing as a country."
Kenyans say mutual distrust between Odinga and Kibaki is a major obstacle to any solution.
Kibaki has said he is ready to form "a government of national unity". But Odinga wants him to step down and hold internationally mediated talks to agree on a "transitional arrangement" before a new vote in three to six months.
Around the country of 36 million people, the poor in city slums and rural areas have been worst hit. The political elite, other affluent Kenyans and expatriates have been largely unaffected in guarded compounds.
The election dispute unleashed protests, riots and anarchy that have scattered refugees across a nation more used to helping those fleeing from countries like Sudan and Somalia.
Eleven U.N. trucks were heading to western Kenya, the heart of the refugee crisis, under police escort on Monday, with enough food to feed 38,000 people for two weeks.
Much of the trouble has pitched opposition supporters against members of Kibaki's Kikuyu tribe, including the massacre of about 30 people sheltering in a church near Eldoret, a western town with decades-old land tensions.
The government said it was investigating claims by some victims of the clashes that they were warned beforehand that if they supported Kibaki "they would pay for it".
"If this is shown to be what occurred, it amounts to pre-meditated murder," it said in a statement.
(Additional reporting by Bryson Hull, Radu Sigheti, Helen Nyambura-Mwaura, Duncan Miriri, George Obulutsa and Alistair Thomson)