Additional riot police were deployed inside Kenya's national election tallying centre overnight, after a crowd of men scuffled in the early hours of Sunday and a party official shouted accusations into the microphone.

The fracas underscored fraying tempers and high tensions within the national counting hall as the country waits for official results from last Tuesday's election. There were wry digs online over the melee from citizens pointing out that the rest of the nation is waiting patiently.

In the presidential race, results so far show a tight race between left-leaning opposition leader Raila Odinga and self-made businessman Deputy President William Ruto.

But confusion over vote tallying by the media and a slow pace by the electoral commission have fed anxiety in Kenya, which is East Africa's richest and most stable nation but which has a history of violence following disputed elections.

Reuters was unable to get access to the official running vote tally for the presidential race on Sunday. A live feed displaying the results at the national tallying center had disappeared hours ago.

When asked about the tally, a spokeswoman for the commission referred Reuters to the live feed. Other electoral officials said they were unable to provide the information.

Officially verified results on Saturday with just over 26% of votes counted put Odinga in the lead with 54% of the vote, while Ruto had 45%.

The winner must get 50% of votes plus one. The commission has seven days from the vote to declare the winners.

A Reuters tally of 255 out of 291 preliminary constituency-level results at 0900 GMT on Sunday showed Ruto in the lead with 52% and Odinga at just over 47%. Two minor candidates shared less than a percent between them.

Reuters did not include 19 forms in the count because they lacked signatures, totals, were illegible or had other problems.

The preliminary tally is based on forms that are subject to revision if any discrepancies are discovered during the official verification process.

The many checks and balances are designed to try to prevent the kind of allegations of rigging that provoked violence in 2007, when more than 1,200 people were killed, and in 2017, when more than 100 people were killed.

CHAOS AT THE COUNTING HALL

Odinga and Ruto are vying to succeed President Uhuru Kenyatta, who has served his two-term limit. Kenyatta fell out with Ruto after the last election and has endorsed Odinga for president.

Kenyatta leaves power having laden Kenya with debt for expensive infrastructure projects and without having tackled the endemic corruption that has hollowed out all levels of government. The next president will also take on rapidly rising food and fuel costs.

Ruto's strong showing reflects widespread discontent with Kenyatta's legacy - even in parts of the country where the president has previously swept the vote.

Large numbers of Kenyans also did not vote, saying neither candidate inspired them.

On Sunday, Ruto's party member Johnson Sakaja won the governorship of the capital Nairobi, the wealthiest and most populous of the 47 counties.

TENSIONS AT TALLYING CENTRE

As the tight race continued, party agents have grown increasinGly agitated at the tallying centre, known as Bomas. Late on Saturday, Raila Odinga's chief agent Saitabao ole Kanchory grabbed a microphone and announced "Bomas of Kenya is a scene of crime," before officials switched off his microphone.

Party agents scuffled with each other, with police and with election officials, at one point trying to drag one official outside.

The scenes, broadcast on national news, were met with bemusement by Kenyans, who urged their leaders to grow up.

"The reckless behavior at Bomas by so-called leaders, which can fast ignite the country, must be called out," tweeted Alamin Kimathi, a human rights activist. "Let the drama end. Let the process continue."

(Writing by Katharine Houreld; Editing by Frances Kerry)