NAIROBI, Kenya — Kenya’s president yesterday invited his chief rival to his official residence to discuss how to end the country’s election standoff, just hours after the opposition called off nationwide rallies amid fears of new bloodshed.

The signs of softening by both sides came after three days of talks with the top American diplomat for Africa. The African Union president, whose trip to Kenya had been delayed repeatedly as the government rejected outside mediation in the disputed vote, is to begin talks in the capital as early as tomorrow.

The American envoy, Jendayi Frazer, said the vote count was rigged, but declined to blame either President Kibaki or Raila Odinga, the opposition leader.

“Yes, there was rigging,” Ms. Frazer told the Associated Press. “I mean there were problems with the vote counting process … both the parties could have rigged.”

Mr. Kibaki, who was re-elected after the disputed vote tally, invited Mr. Odinga to the State House for a meeting Friday to discuss how to end the political and ethnic turmoil that has already killed some 500 people, according to a statement from the president’s press service.

A particularly troubling aspect of the political violence has been its degeneration in some areas into rioting pitting other tribes against Mr. Kibaki’s Kikuyu, long dominant in Kenya’s politics and economy.

Reports of ethnic killings continued to stream in from the countryside, with an official in neighboring Uganda confirming 30 Kenyan refugees were thrown into the border river by attackers, and were presumed drowned.

Two Ugandan truck drivers carrying the group said they were stopped Saturday at a roadblock mounted by militiamen who identified the refugees as members of Mr. Kibaki’s Kikuyu tribe and threw them into the deep, swift-flowing Kipkaren River, a Ugandan border official, Himbaza Hashaka, said.

The drivers said none survived, Mr. Hashaka said.

A statement yesterday from the Ministry of Special Programs put the death toll at 486 with some 255,000 people displaced from their homes. The toll, which did not include the drownings, was compiled by a committee of humanitarian services set up by the government, which toured areas most affected by riots and protests.

Among those killed was Lucas Sang, an Olympic runner who made the quarter finals of the men’s 400-meter race in 1988 and the same year ran in the finals as a member of the 4x400m relay. Mr. Sang, a member of the Kalenjin tribe that has clashed with Kikuyu, was found in western Kenya New Year’s Eve with a deep gash to the back of his head and his body badly burned, said Moses Tanui, a former world 10,000-meter champion who was a close friend. Mr. Sang was in his 50s.

Mr. Odinga called off protests after meeting with Ms. Frazer and after Mr. Kibaki’s government said today’s proposed demonstrations were illegal and could provoke violence.

The combination of diplomacy and plain speaking may be particularly effective coming from America, one of Kenya’s major donors, with overall aid amounting to about a billion dollars annually, according to an American Embassy spokesman, T.J. Dowling. Remittances and bilateral private trade between the countries accounts for another billion dollars, he said.

Kenya, strategically located in the Horn of Africa and neighboring hotspots Sudan and Somalia, has turned over dozens of suspected terrorists to America. The East African nation allows American forces to operate from Kenyan bases and a small team of American military officers train the Kenyan army on counterterrorism and coastal protection.