Posted with permission from dpa German Press Agency

Nairobi (dpa) - Incumbent President Uhuru Kenyatta has pleaded for peace and unity after being declared the winner of Kenya's hotly contested presidential poll.

The 55-year-old, who has been in office since 2013, won a second five-year term with 54.27 per cent of the vote, followed by 72-year-old opposition leader Raila Odinga with 44.74 per cent, the electoral commission said on Friday.

It remained unclear whether Odinga and his opposition coalition National Super Alliance (NASA) would accept the results, after they alleged earlier this week that hackers had manipulated the voting system.

"I reach out to all ... we shall work together, we shall grow together, we shall develop this country together ... so we can build this nation of ours together," Kenyatta said immediately after the results were announced.

"Elections come and go. Kenya is here to stay. Always remember that we are brothers and sisters," the president-elect said. "Let us be peaceful ... there is no need for violence."

There were celebrations and protests across the country after his win was confirmed, with television footage from early Saturday showing Kenyatta supporters dancing on the streets.

However, protests were reported in the western city of Kisumu, an opposition stronghold, as well as in the Nairobi slum of Kawangware, where a dpa reporter saw police using tear gas to break up demonstrators.

Electoral commission chairman Wafula Chebukati announced the result after the commission painstakingly double-checked the tally of the electronic voting system with the results of the paper-based forms from all of the East African nation's 290 constituencies.

The additional verification process was instituted after concerns over hacking were raised by the opposition after Tuesday's vote.

Shortly before the final tally was declared on Friday, NASA said it was "not going to be party" to the announcement, because their concerns over the vote were not "adequately addressed."

Representatives of the opposition coalition then exited the main electoral centre in the capital, Nairobi.

Tensions had been rising throughout Kenya as the announcement of final results was postponed repeatedly on Friday, as tallies from the constituencies trickled in slowly for verification.

"I know there is a lot of anxiety [but] it's more important to be accurate than to rush the process," said electoral commission chief executive Ezra Chiloba.

The electoral commission earlier this week admitted that hackers had tried to access its database, but said they did not succeed.

But the opposition insisted it was in possession of alternative results, showing Odinga in the lead.

"The results published by the electoral commission are a fraud," NASA member John Mbadi reiterated during a press conference on Friday morning.

"Our independent analysis done by our experts has shown that [Odinga] won this election square," Mbadi added.

Later on Friday, NASA said it was would only accept the election result if it was granted access to the electoral commission's servers to double-check the polling data.

International election observers however found few irregularities and called the vote credible.

"We expect now a sense of responsibility and leadership by all parties," the European Union said in a statement on Friday.

Eight candidates were in the running for president, but the election was effectively a two-horse race between Kenyatta and Odinga. Both are sons of late independence fighters: Kenya's first president Jomo Kenyatta and his deputy, Oginga Odinga.

Concerns remained on Friday that a refusal by the opposition to accept the result could spark ethnically based violence in an echo of the 2007 elections, when Odinga was defeated by Mwai Kibaki.

Many people believed he was rigged out of victory and 1,200 people were killed in the unrest that followed.