Kenyan Attorney General Amos Wako has called for an independent investigation into vote results that led to President Mwai Kibaki's disputed re-election.
Mr Wako said on national television that "a proper tally of the valid certificates returned and confirmed should be undertaken immediately".
His call came as a planned opposition rally in Nairobi was postponed amid clashes between supporters and police.
More than 300 people have been killed and some 70,000 displaced since Sunday.
The violence was triggered by claims of vote rigging in the 27 December presidential election.
Mr Kibaki on Thursday called for an end to the unrest and said that once that had happened he would be prepared to speak to the opposition.
"I am ready to have dialogue with the concerned parties once the nation is calm and the political temperatures are lowered enough for constructive and productive engagement," Mr Kibaki told journalists at his State House residence in Nairobi.
Earlier, a spokeswoman for European Union foreign policy chief Javier Solana said that the EU and US had agreed to push Mr Kibaki and his opposition rival to consider a coalition government, following talks between Mr Solana and US Secretary of State Condoleezza Rice.
However, US State Department spokesman Sean McCormack later said that was not what was agreed.
"It's not quite how the secretary, at least from our side, would characterise the situation," Mr McCormack said.
"We're not going to dictate the outcome of any discussions between the two parties," he added, saying that the US was urging both sides to "have a political dialogue that leads to a political solution, whatever that may be".
The Orange Democratic Movement (ODM) has claimed its leader Raila Odinga is the "people's president" and has demanded a re-run of the poll.
Police used tear gas and water cannon to disperse thousands of opposition supporters on Thursday as they tried to hold a banned rally in the Kenyan capital's Uhuru (Freedom) Park.
Demonstrators poured out of Kibera slum and other shanty towns after dawn but were prevented from reaching the centre of Nairobi by a massive security presence.
The opposition has decided to postpone the event for now. However, there were conflicting reports about when the rally would be rescheduled - some party officials said Friday 4 January and others said Tuesday 8.
There were also running battles between police and youths in the coastal city of Mombasa.
In the township of Bombolulu on its northern fringes, police fired live rounds over the heads of a group of demonstrators, who chanted: "No peace!"
And the BBC's Karen Allen in Eldoret says targeted arson attacks continue in the western Kenyan town, where at least 30 died on Tuesday when a church was set alight.
The latest disorder prompted the Nairobi Stock Exchange to shut
South African Archbishop Desmond Tutu has flown in to try to mediate in the crisis.
The Nobel laureate was quoted by Reuters news agency as saying: "This is a country that has been held up as a model of stability. This picture has been shattered."
However, plans for African Union leader John Kufuor to travel to Kenya on Thursday to spearhead mediation efforts were abruptly cancelled.
The latest disorder prompted the Nairobi Stock Exchange to close barely an hour after opening.
Supporters of President Kibaki (a member of Kenya's predominant Kikuyu tribe) and Mr Odinga (from the Luo community) have accused each other of genocide and ethnic cleansing in the post-poll unrest.
Mr Kibaki invited all MPs to crisis talks at state house on Wednesday but Mr Odinga's Orange Democratic Movement refused and demanded the president quit.
Samuel Kivuitu, head of Kenya's election commission, which declared that Mr Kibaki had been re-elected, has told the BBC he could not say for sure if he had won the poll fairly.