Updated

The official death toll from post-election violence in Kenya rose to 575 on Sunday as rights groups accused police of employing an unofficial "shoot to kill" policy against protesters.

Hundreds of bodies have been counted since violence and ethnic warfare erupted in the East African nation following the disputed Dec. 27 presidential election, Kenya Red Cross Society spokesman Anthony Mwangi said.

But some fear the real figure is even higher.

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"My greatest fear is that when the authorities and rescuers have combed every village, they will discover that many, many people have been massacred,"

Mutuma Mathiu, managing editor of The Sunday Nation, wrote in an editorial.

"I have heard about the bodies of children, some half burnt, others half-eaten by animals, rotting in the killing fields that Kenya has become," he wrote.

Kenya's opposition, meanwhile, called for three days of nationwide protests starting Wednesday following the collapse of international mediation to break a deadlock between President Mwai Kibaki, who claimed election victory, and opposition leader Raila Odinga, who has alleged fraud.

African Union chairman President John Kufuor of Ghana and U.S. envoy Jendayi Frazer failed last week to persuade Kibaki and Odinga to agree even to meet. Frazer said Saturday that Kibaki and Odinga must meet and acknowledge "serious irregularities" in the vote count.

Former U.N. Secretary-General Kofi Annan is expected by Tuesday to mediate. The British Foreign Office has said Annan will work with Graca Machel, wife of Nobel laureate Nelson Mandela, and former Tanzanian President Benjamin Mkapa.

On Sunday, U.S.-based Human Rights Watch accused Kenyan police of shooting at protesters. "Kenyan police in several cities have used live ammunition to disperse protesters and disperse looters, killing and wounding dozens," the group said.

Witnesses in Nairobi reported unarmed civilians hit by police gunfire, including a woman hit by stray bullets penetrating the wall of her home; a man shot in the leg, and a boy shot in the chest while watching a protest from the door of his home, the group said.

Human Rights Watch quoted an unnamed Kenyan police source as telling monitors: "Many of us are unhappy with what we are being asked to do. This 'shoot to kill' policy is illegal, and it is not right. We have brothers and sisters, sons and daughters out there."

Police denied the accusations.

Officers have "acted strictly within the laws of this country," police spokesman Eric Kiraithe said. "In fact, some of the complaints we are receiving are from property owners that police failed to use all the powers under the laws to protect their property."

Kenya's Anglican bishops also called on police to stop firing their guns.

In a Nairobi slum, the Red Cross handed out food Sunday to some of the 255,000 people forced from their homes by the violence.

"They have lost everything. There is nowhere they can go," said Red Cross volunteer Jane Olago. "Some of them talk like they wish they were dead; they have lost hope in life."