A top US envoy on Monday led an international push for rival Kenyan leaders to end turmoil that has left hundreds dead while the opposition vowed to stage new rallies.
The government repeated a warning that all political rallies were banned, after a string of deadly clashes linked to the December 27 poll that the opposition claims was rigged.
More than 370 people have died in post-poll violence and aid groups have warned of a humanitarian crisis with some 250,000 people displaced, particularly in the west of the country and the capital's slums.
US Assistant Secretary of State for African Affairs Jendayi Frazer held a third day of talks with the camps of President Mwai Kibaki and opposition leader Raila Odinga in a bid to ease the tensions.
South African Nobel peace laureate Desmond Tutu took part in negotiations.
A British embassy official said London had mounted a "behind the scene" push for a political deal in its former colony. Ghana's President John Kufuor, current head of the African Union, is also expected in Kenya this week for talks with the rivals.
The government on Sunday said it had sent envoys across Africa to seek backing in the crisis that has caused international concern because Kenya has been a pillar of stability in a region blighted by conflict.
"We have sent envoys to African countries with a special message to leaders that presents a clear picture of the political and security situation in the country," government spokesman Alfred Mutua told AFP.
Odinga, who claims Kibaki rigged the election and has called for his resignation, rejected a weekend offer for a unity cabinet from Kibaki.
"We are not interested in Kibaki's solution to this problem. He has nothing to offer because he did not win these elections," the opposition leader said.
Odinga's camp plans to hold nationwide demonstrations on Tuesday over alleged vote-rigging, nearly a week after police blocked an initial rally.
The government reaffirmed that demonstrations would not be tolerated. "The government has banned all political party rallies," spokesman Mutua told a news conference.
ODM-Kenya leader Kalonzo Musyoka, who finished third in the polls, pressed for dialogue, saying he was ready to meet Kibaki and Odinga to end the stand-off.
Poll monitors have said the vote-count was rife with irregularities with both sides trading accusations of rigging.
The electoral board nevertheless declared Kibaki the winner, unleashing a wave of nationwide riots that quickly devolved into deadly tribal vendettas, notably between Kibaki's Kikuyu tribe and Odinga's Luo.
At least 371 people have been killed in unrest since election day, according to a tally compiled by AFP from hospitals, police and mortuaries.
Police said seven people were killed in Transoia district in western Kenya when they attempted to attack a police station where displaced people had taken refuge.
The UN estimates the chaos has displaced some 250,000 Kenyans, including some 100,000 who need immediate help in the western Rift Valley region, scene of some of the worst fighting.
Aid groups warned of a health emergency in makeshift camps in schools, hospitals and churches in the area, most of which were still out of reach owing to their inaccessibility or safety concerns.
The World Food Program said that a first escorted convoy of food left Mombasa Sunday, carrying some 670 tons of food towards Nairobi and Eldoret.
The government has delayed the opening of schools, due to begin Monday, by one week.
Washington considers Kenya a key ally and a beacon of stability in the region. Frazer was due to give a news conference later Monday.
Meanwhile police offered security to oil tankers taking fuel to neighboring countries in a bid to end shortages in Uganda, Burundi, Rwanda and the eastern Democratic Republic of Congo.
