Nairobi (AFP) - Kenya found itself in a dangerous limbo on Friday as violent protests rocked opposition strongholds a day after a deeply divisive election that has left eight people dead.

Plans to restage elections in the western Nyanza region where violence blocked voting on Thursday were again delayed as election chief Wafula Chebukati said he feared for the safety of his staff.

The worst crisis in Kenya in a decade, has cast a shadow over east Africa's most stable democracy and economic powerhouse.

Two people were shot dead Friday as protests raged in western towns and clashes erupted in a Nairobi slum while election officials counted votes from a ballot set to hand President Uhuru Kenyatta a landslide win after a boycott by his rival Raila Odinga.

Initial figures suggested only about a third of registered voters turned up, tarnishing the credibility of an election boycotted by many of the 19.6 million registered voters.

In Nairobi's Kawangware slum, one man was shot dead by police as clashes erupted between ethnic groups, police said.

A witness told AFP the violence started when a group of youths "started attacking people and questioning why people never voted".

"That’s when an all-out war broke out," said local resident Josphat Ochwaya, adding that the perpetrators fled when the police turned up, but continued hurling stones at each other and at the police, who opened fire, killing one.

An AFP correspondent in the slum also saw opposition supporters setting light to shops belonging to members of Kenyatta's Kikuyu tribe.

A group of young men wielding machetes could also be seen roaming around, and an AFP photographer saw a man with a deep gash to the back of his head.

A man was also shot dead during a confrontation with police in the western town of Bungoma, witnesses and police said, raising to eight the number of people killed in two days of election-related unrest.

Around 50 others were wounded on Thursday, most of them by live bullets, according to an AFP tally from officials and medics.

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The confirmed casualties raise to 48 the number of people killed in election-related violence since the annulled August poll, with Human Rights Watch demanding the leaders take action.

"Kenya's repeat elections have been marred by violent protests, killings and beatings in key opposition strongholds in coastal, western and eastern parts of Kenya," said Otsieno Namwaya, Africa researcher at the New York-based watchdog.

"Kenyan leaders should call for calm, ensure that police exercise restraint in responding to protests and that there is accountability for unlawful use of force."

- Call for calm -

International observers issued a joint statement calling for calm and urging Kenyans "to refrain from unlawful acts and respect the rights of fellow citizens" including election staff.

They said it was "imperative that the security forces provide protection to all citizens and avoid the excessive use of force".

The crisis is the worst since a 2007 election sparked politically-driven ethnic violence that left 1,100 people dead.

Thursday's vote was the chaotic climax of a two-month political drama that began when the Supreme Court overturned Kenyatta's victory in the August 8 election over "irregularities".

Odinga refused to take part in the re-run on the grounds the election commission had failed to make the necessary changes to ensure a free and fair vote and his supporters barricaded polling stations and blocked voting in several areas.

Thursday's violence prompted the Independent Electoral and Boundaries Commission (IEBC) to delay elections in western counties until Saturday. But as the violence spilled into Friday, Chebukati said Saturday's vote would be delayed to a "further date to be announced in the coming days".

According to the Supreme Court ruling, the election re-run must be completed by October 31.

It was unclear clear how the delay would affect the announcement of poll results.

- More unstable than ever -

While the Supreme Court ruling was hailed as a chance to deepen democracy, the acrimonious bickering between Odinga and Kenyatta -- whose fathers were rivals before them -- has sharply divided a country where politics is already polarised along tribal lines.

Kenya is now "more fractured and unstable than ever before", the Daily Nation concluded in an editorial Friday.

Odinga has vowed a campaign of "civil disobedience" and is demanding another new election be held within 90 days.

Kenya has so far spent some $500 million (431 million euros) on two elections in three months.

While the August election saw long queues of voters, Thursday's vote was a different story with many polling stations empty or welcoming only a trickle of people.

Election officials said data showed less than 35 percent of voters had cast ballots.

"The message sent by the population (Thursday) was very clear, and I don't think you have to force the election, otherwise there will be more deaths," a polling officer in Kisumu said on condition of anonymity.