Kenya's opposition vowed to defy police for a second day running on tomorrow and try to hold a mass rally in the capital.
Efforts by the opposition to stage the banned protest today were met by police firing teargas and warning shots as thousands of people tried to march on the city centre.
Meanwhile Kenya's president, Mwai Kibaki, has offered to talk to political rivals after a day of battles between police and anti-government protesters.
'I am ready to have dialogue with the concerned parties once the nation is calm,' Mr Kibaki said.
'I am deeply disturbed by the senseless violence instigated by some leaders,' Mr Kabaki continued. He also said that 'those who continue to violate the law will face its full force.'
US President George W. Bush urged Kenyans to refrain from further violence and called on Mr Kibaki and opposition leader Ralia Odinga to 'come together' to resolve the dispute.
'It's very important for the people of Kenya to not resort to violence,' Mr Bush said.
Kenya's Attorney General has called for an independent investigation into the re-election of President Mwai Kibaki.
More than 300 people have died in a wave of violence since Sunday's disputed election result.
Earlier today, an opposition rally in Nairobi was called off in an attempt to end running battles between police and protesters.
An opposition official said they did not want any more lives lost and they would now hold what he called a peaceful meeting next week.
A Kenyan police spokesman said his officers had been doing their best to calm the situation.
Police had fired tear gas and water cannon as thousands of protesters made their way to the banned rally.
The opposition leader, Raila Odinga, had urged his supporters to attend the rally in the capital in spite of a government ban.
Mr Odinga said his country had reached a defining moment, and that it needed help from the international community.
South African Archbishop Desmond Tutu has flown to Nairobi to try to mediate in the crisis.
Speaking on RTÉ Radio's Morning Ireland, Steve Bloomfield, a reporter for Global Radio News and writer for The Independent, described the situation in the capital early today.
'Sporadic gunfire was heard throughout Nairobi this morning. Parts of the slums in Kibera and Mathare appear to be on fire.
'Riot police are out in full force trying to block off all the major routes into town to prevent people getting to this planned demonstration,' he said.
Also on the programme, Richard Dowden from the Royal African Society said it would be difficult to find a political solution to the situation.
'The rational result would be for a recount under international or at least neutral supervision and a complete review of the whole election process,' he said.
Meanwhile, Uganda has closed its border with Kenya for business, but is allowing refugees to cross.
Human rights groups say 1,000 Kenyan refugees have already crossed into Uganda.
