Kenya's opposition plans more street protests on Tuesday to try to force out President Mwai Kibaki, while also meeting international mediators to discuss how to end turmoil that has killed more than 300 people.

Orange Democratic Movement (ODM) leader Raila Odinga - who says he is Kenya's real president - was to see the top U.S. diplomat for Africa, Jendayi Frazer, on Monday.

But his supporters say they will not give up on demonstrations despite a police ban. ODM says nationwide rallies are scheduled for Tuesday.

Protests against Kibaki's disputed re-election brought Nairobi and other towns to a standstill last week, as police battled furious Odinga supporters. Dozens have died in protests.

Odinga faces the dilemma of responding to international pressure to avoid anything that may provoke more violence and maintaining pressure to oust Kibaki.

"Nobody wants to spill blood, but democracy has no shortcut," Odinga aide Tony Gachoka told Reuters. "If you don't engage (on the street), the dictator entrenches."

Kibaki's government accused Odinga of "grandstanding" and setting impossible conditions for talks to end the unrest in east Africa's largest economy.

Around the country of 36 million people, Kenyans were struggling to come to terms with some of the worst violence in their nation since independence from Britain.

The poor in city slums and rural areas have been worst-hit by the violence, with the political elite, other well-to-do Kenyans and expatriates largely unaffected in gated compounds.

Odinga, who turned 63 on Monday, had looked on course to win the December 27 vote until Kibaki, 76, was handed a narrow victory.

Both sides alleged fraud, and international observers say the election fell short of democratic standards.

The dispute unleashed protests, riots and anarchy that have left nearly 200,00 refugees in a nation more used to helping those fleeing from countries like Sudan and Somalia.

The Daily Nation newspaper called it "the darkest week since the country won independence in 1963."

"IMPOSED HISTORY"

Much of the violence 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 town in western Kenya with decades-old land tensions.

Kenyans are aghast at images beamed around the world of the chaos in their nation, a popular tourist destination and regional base for numerous international institutions.

But many are also offended at superficial depictions of tribal warfare that do not explore the many other roots of the violence: land disputes dating back to colonial times, wealth disparities, and incitement by politicians.

"While tribalism is an issue in Africa, it is not some weird atavistic African sentiment but a logical result of Africa's imposed history," wrote Richard Dowden, director of the London-based Royal African Society.

"There is, in normal times, little personal conflict between people of different ethnicity."

Another Africa expert, Caroline Elkins of Harvard, said disputes between Kibaki's Kikuyu tribe and members of Odinga's Luo community were nothing new.

"The British had spent decades trying to keep the Luo and Kikuyu divided, quite rightly fearing that if the two groups ever united, their combined power could bring down the colonial order," she said.

There was, however, increasing concern across Kenya at population shifts sparked by the turmoil, most notably Kikuyus fleeing back to their central highland homelands between Nairobi and Mount Kenya.

African Union Chairman John Kufuor, Ghana's president, was due to visit this week to try to mediate between Odinga and Kibaki. Their mutual distrust is a key obstacle to a solution.

Kibaki has said he is ready to form "a government of national unity." But Odinga wants him to renounce the presidency, hold talks through an international mediator, and enter a "transitional arrangement" prior to a new vote.