Kenya's main monitoring group backed the official result of this week's ballot on Saturday as opposition anger at the re-election of President Uhuru Kenyatta erupted in the western city of Kisumu and slums ringing the capital, leading to two deaths.
In Nairobi, a young girl was shot dead by police firing "sporadic shots" at protesters in Mathare, a witness said. The run-down neighbourhood is loyal to opposition leader Raila Odinga, whose party has rejected the results of Tuesday's vote as a "charade".
A government official told reporters another man was killed in Kisumu county, centre of serious post-election ethnic violence in 2007 in which 1,200 people were killed and 600,000 displaced.
Kisumu's main hospital was treating four people brought in overnight with gun-shot wounds and six who had been beaten by police, hospital records showed.
One man, 28-year-old Moses Oduor, was inside his home in the impoverished district of Obunga when police barged in after midnight as part of house-to-house raids, dragging him out of his bedroom and laying into him with clubs.
"He was not out fighting them, he was rescued by my sister who lives next to him, she came outside screaming at the police asking why they are beating people," his brother, Charles Ochieng said, speaking on behalf of a dazed Oduor.
More shooting was heard outside the hospital on Saturday morning. In Nairobi, Kenyan television showed footage of armed police units backed by water cannon moving through the rubble-strewn streets of Kibera, another pro-Odinga Nairobi slum.
The election commission announced its official results late on Friday, giving 55-year-old Kenyatta another five years in power after securing 54.3 percent of votes cast.
Odinga's NASA coalition rejected the results even before they were announced, saying that the election commission's systems had been hacked, that the conduct of the count was irregular and that foreign observers who gave the poll a clean bill of health were biased.
However, the main monitoring group, ELOG, which had 8,300 observers on the ground, said its parallel vote tally conformed with the official outcome.
ELOG's projected outcome put Kenyatta on 54 percent, compared with the official figure of 54.3 percent. This was well within ELOG's 1.9 percent margin of error, the group said.
"We did not find anything deliberately manipulated," Regina Opondo, the chairwoman of ElOG's steering committee, told a news conference.