The main Kenyan presidential candidates have held final rallies in the capital, Nairobi, before Thursday's vote, tipped to be the closest in Kenyan history.
Nobody seemed to be seriously injured during the post-rally scuffles
The current President, Mwai Kibaki, addressed a big rally in the city's main park while his main rival, Raila Odinga, spoke at a sports stadium.
Mr Kibaki has been campaigning on his economic record while Mr Odinga has focused on tackling corruption.
Rival supporters clashed briefly after the rallies and police fired tear gas.
Several people were hurt in the clashes during which stones were thrown. The atmosphere in the city has been highly charged.
Dozens of people have been killed and hundreds have been made homeless in election-related violence since the campaign began.
'No grumpy old men'
Thousands of people attended the rival rallies, described by correspondents as huge.
Mwai Kibaki came to power on a reform platform
"Everybody can see the work I have done in the past five years," Mr Kibaki told the crowd in Uhuru (Freedom) Park as he appealed for a second term in office.
"You all know what we have been doing and I am asking for your votes so that I can continue working."
He took the chance to dismiss his opponent, a former member of his cabinet who was sacked in 2005 for opposing government policy, as someone who had been "defeated by the work".
At the stadium a few kilometres away, Mr Odinga promised to sweep away Kenya's old guard, in an apparent reference to his 76-year-old rival's age.
"We will not be an exclusive club of grumpy old men," said the 62-year-old, who has been consistently ahead in the polls.
He also warned against any attempt to rig the election.
This promises to be the closest election since Kenya became a republic more than 40 years ago, the BBC's Adam Mynott reports from Nairobi.
Raila Odinga was once an ally of his rival for the presidency
This accounts for many outbreaks of serious election-related violence in western parts of the country.
Samel Kivuiti, head of Kenya's electoral commission, says that ethnic tension underlying the fighting is the biggest threat to free and fair elections.
Both of the leading candidates have urged their supporters to shun divisive, ethnically based allegiances but other politicians in their campaigns have used ethnicity to add to tension, our correspondent says.
The third of the main presidential aspirants, Kalonzo Musyoka from the small Kamba, tribe has tried to make his appeal non-ethnic but commentators say he has been forced to do so because the Kamba number so few.
With no campaigning allowed on Wednesday, Boxing Day, Monday was the last day for the candidates to woo undecided voters out of an electorate of more than 14 million.
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