(CNN)- Children's bodies were piled in a Nairobi morgue, churches burned and police on horseback chased pedestrians through the streets as Kenya's political crisis stretched into a fifth day Thursday.
Meanwhile, the country's attorney general called for a recount and independent investigation into the December 27 election in which incumbent President Mwai Kibaki was declared the victor over opposition candidate Raila Odinga .
Violent protests ensued after results were announced Sunday and the number of dead has surpassed 300 people.
At a Nairobi morgue on Thursday, Odinga toured freezing rooms of the dead and saw the bodies of babies and children piled on shelves, according to an Associated Press report. It was unclear when those in the morgue died, but Odinga supporters said some died on Thursday.
"What we have just seen defies description," Odinga told journalists after visiting the morgue. "We can only describe it as genocide on a grand scale."
Odinga called off a "million man" rally planned for a Nairobi park on Thursday, but not before police clashed with his supporters heading to the event.
Images provided to CNN by I-Reporter Duncan Musicha Waswa showed riot police on horseback chasing citizens on Nairobi's Bunyala Road. Those going about their daily business raised their hands to avoid the wrath of police, Waswa told CNN.
Odinga supporters carried white flags, olive branches and protest signs as they tried to get to Uhuru Park, where the rally was to have been held.
Government forces used tear gas and water cannon to disperse the crowds.
"We are a peaceful people who do not want violence," William Ruto , a top official with Odinga's party told The AP. "That is why we are peacefully dispersing now."
Odinga called the meeting despite a government ban on such gatherings, having been forced to abandon his first attempt on Monday soon after the onset of the conflict.
Despite this week's two failed gatherings, the opposition Orange Democratic Movement now hopes to hold one Friday to protest the result of the elections.
Meanwhile, Kenyan Attorney General Amos Wako called for a recount and a government of national unity, according to a statement from his office.
Wako, who has been Kenya's attorney general since 1991, oversaw the nation's transition from one-party rule to democracy that year.
"Such an exercise will go a long way in assuaging the inflamed passions of the people," Wako said in a written statement. "The level and nature of the violent protest has never before been witnessed in our country and is quickly degenerating into a catastrophe of unimaginable proportions."
Also Thursday, Archbishop Desmond Tutu began meeting with opposition officials, including Odinga , in an effort to mediate the election dispute.
"We've come to express our solidarity with the people of Kenya to express our sympathy at the carnage that has happened, hoping that we will be able to encourage the leadership to take action that would stop that carnage," Tutu said.
It was not immediately clear if the Nobel laureate would also talk with Kibaki's party.
In a Thursday news conference, Kibaki appealed for calm. He condemned the "senseless violence," which he said is causing an "unnecessary loss of lives, destruction of property, and displacement of innocent ... from their homes." Video Watch Kibaki condemn the violence "
"I am ready to have dialogue with concerned parties once the nation is calm and the political temperatures are lowered enough for constructive and productive engagement," he said.
In Washington, the State Department said Assistant Secretary of State for African Affairs Jendayi Frazer, America's top diplomat for Africa, was headed to Nairobi to put pressure on leaders to stop the bloodshed.
Odinga's supporters had slowly made their way to Uhuru Park for the rally, but were met by government security forces.
"There are fewer protesters here than there are guards," journalist David McKenzie said from the Nairobi slum of Kibera before the rally was canceled.
"But earlier, tear gas was thrown at them, and then there were running battles up and down the street ... with water cannon spraying and dispersing the people here."
There were also reports of government troops firing live rounds above protesters' heads, as the smoke of tires being burned in protest began to choke the air over the capital. Flames also could be seen leaping from some of the shacks that fill the capital's slums.
At least one church was burning. As many as 75,000 people have been internally displaced by the violence, the government said on Tuesday.
Violence erupted in the normally peaceful African country over the weekend, as frustration mounted at the slow pace of vote counting. It came to a head after the nation's Election Commission announced Sunday that the incumbent Kibaki won with 51.3 percent of the vote, while Odinga had 48.7 percent.
Kibaki is a member of the Kikuyu, Kenya's largest ethnic group which comprises roughly 22 percent of the country's population. Odinga belongs to the Luo group, which makes up about 13 percent of Kenya's population.
A local reporter on Wednesday told CNN he witnessed youths from minority ethnic groups manning checkpoints outside Eldoret , about 185 miles (300 kilometers) northwest of Nairobi, and refusing entry to members of the Kikuyu ethnic group.
Kenyans are required to carry identification cards, and a person's name often indicates what ethnic group they are from.