Nairobi (CNN) Kenyan police clashed with protesters in opposition strongholds, leaving one person dead and more injured as the nation voted for a new president Thursday.

The main opposition candidate had urged his supporters to boycott the election -- the second in less than three months -- reflecting bitter divisions in the country.

Voting appeared peaceful in most of the country, though the electoral commission said turnout was only an estimated 48%.

But tensions ran high in the western town of Kisumu and the Kibera slum area in Nairobi, both bastions of support for opposition leader Raila Odinga.

Voting materials arrived in Kisumu, but electoral commission officials could not be found at some polling stations. Many Kisumu residents were staying away from the polls as a protest.

Police used tear gas and water cannons on opposition supporters in the city. One person died from a gunshot wound and four others were hospitalized with bullet wounds, Kisumu hospital officials said.

Kenyan police officials did not respond to CNN's numerous calls for comment about reports of clashes in Kisumu.

Opposition supporters burn tires during protests in Kisumu on Thursday.

In Nairobi, security was tight as soldiers equipped with long guns and tear gas canisters hovered near polling stations.

Kenyan officers charge at stone-throwing residents during clashes in Kibera on Thursday

In Kibera, the main opposition stronghold in the city, protesters pelted police with stones as officers used tear gas and fired into the air as a warning to disperse.

"There is no voting here, leave us alone," protesters shouted. "No Raila, no peace!"

'Happy to vote'

The scene was peaceful, however, in Kiambu, an area north of Nairobi where support for incumbent President Uhuru Kenyatta is strong.

Josephine Wambui, 93, woke up at dawn to wait for her son to take her to the polling station there. She told CNN she had voted in every election since Kenya gained independence in 1963, and this would be no different.

"I am happy to vote. It is just a matter of coming to the polls and exercising my right," she said. "I have a rightful civic duty to perform."

Kenyans queue to vote just after dawn on Thursday.

The opposition boycott is expected to hand victory to Kenyatta, but the poll will be affected by the low turnout and is likely to face legal challenges.

Speaking on national TV, the chairman of Kenya's electoral board, Wafula Chebukati, said the vote had been postponed until Saturday in five counties: Kisumu, Siaya, Migori, Homabay, Busia. All five are areas where opposition support is high.

Most polls were to close at 5 p.m. local time, he said, although some have been extended due to "logistical challenges" in opening on time. Chebukati said more than 5,000 stations did not open, but bad weather and security issues were a factor at some.

A Kenyan policeman sits outside an empty polling station in Mombasa on Thursday.

According to the Kenyan Constitution, electoral officials must declare final results within seven days. It is not immediately clear if postponing the vote in certain areas will affect that deadline.

Linus Kaikai, chairman of Kenya Editors Guild, said the opposition proved to be too strong in its heartland.

"It's very unlikely another try (at holding an election) will work at all because the clear message from that side of the country and the leadership of the opposition is they cannot take part in this exercise," he added.

"They want the reforms they have demanded to be carried out in the IEBC, they basically want a different environment and a new general election altogether."

Bitter divisions

The election comes after weeks of political twists and turns.

While the high court ruling appeared to vindicate Odinga, the opposition leader dropped out of the race this month, saying the electoral commission had not implemented reforms.

A voter verifies her identity at a polling station at Mutomo primary school in Kiambu.

Odinga urged his supporters to boycott the election, raising the possibility that millions will shun the outcome. A day before the election, activists made a last-ditch effort to stop the vote but the Supreme Court failed to rule on the challenge.

The political uncertainty has left residents of the east African economic powerhouse on edge. The election has become so divisive, it has revived fears of violence like that experienced in 2007 and 2008, when at least 1,000 people were killed in Kenya.

After Kenyatta was declared the winner in the August vote, sporadic clashes erupted in some areas, killing at least 24 people.

Leaders urge restraint

In a televised address on the eve of the rerun, Kenyatta urged the public to be peaceful and pledged fair treatment for all.

"After you vote -- and I have said this before -- please go home. Go back to your neighbor. Remember that in spite of their origin, your neighbor is your brother; your neighbor is your sister," he said.

Kenya's President Uhuru Kenyatta casts his ballot.

The President's comments addressed the issue of ethnic bonds, which are often stronger than national identity in Kenya, which has at least 40 ethnic groups.

Kenyatta hails from the country's largest community, the Kikuyu. Mostly originating from Kenya's central highlands, the Kikuyu have long been accused of wielding strong economic and political power in the country. Odinga is a member of the Luo community, which some say has become increasingly marginalized in recent years.

Hours before the President spoke, Odinga appeared at an opposition rally in Nairobi, where he addressed throngs of supporters and called for a "national resistance movement" to boycott the election.

"Do not participate in any way in the sham election," he said. "Convince your friends, neighbors and everyone else not to participate."

Odinga urged Kenyans who "value democracy and justice to hold vigils and prayers away from polling stations." He also issued a call for peace within communities, saying, "Don't look at your brother or sister with suspicion. He or she is as much of a victim as you."

Fears of unrest

Last week, Chebukati, the electoral chief, had warned that he had no faith the country would deliver a free and fair election . He said political leaders were the greatest threat to a credible vote, urging Odinga and Kenyatta to meet and discuss their differences.

Opposition supporter Kepher Omweri, 37, who attended Odinga's rally, said he would not vote because he felt his rights were being denied.

"I'm here to support my presidential candidate and tell the world that here in Kenya, we are being led by dictators. The people who are in power; they are there using their own powers and not those of the people," Omweri said.

Supporters of the National Super Alliance (NASA) opposition leader Raila Odinga gather at Uhuru Park in Nairobi on Wednesday.

Kenyatta supporter John Mwangi said although he voted, the election had lost some excitement with the opposition candidate's boycott.

"Now I just want us to finally have peace so we can move on from this," he said.

Observers will be closely monitoring Thursday's election, including the Carter Center, which also had a team there in August. But it said it will not send as many observers this time because of "growing insecurity" and uncertain political environment.

As the largest economy in East Africa, any unrest could have ripple effects far beyond the nation of 47 million people. Many view Kenya's fate as a key indicator for stability in a region that includes the fledgling Somali government and the politically tense Sudan and South Sudan.