NAIROBI: The opposition is bracing for a protracted legal battle after William Ruto was declared Kenya's new president over the opposition of more than half of the Electoral Commission members.

In the western city of Kisumu and Nairobi's huge Kibera slum, both strongholds of rival candidate Raila Odinga, calm returned to the streets after protesters battled police and burned tyres on the road overnight.

The dramatic events of Monday, which saw Ruto declared president by a tiny margin as a split emerged in the electoral commission overseeing the Aug. 9 vote, has raised fears of bloody violence like that seen after previous disputed polls.

Odinga supporters have denounced Monday's result although Kisumu Governor Anyang' Nyong'o called for calm as protests in parts of the lakeside town turned violent after Ruto's victory was declared.

Makau Mutua, the head of Odinga's campaign think-tank, said officials of his Azimio La Umoja (Declaration of Unity) Alliance were discussing a course of action.

"We are consulting among ourselves," Mutua told. "It is a top line issue ... all options are on the table. No option has been ruled out at this moment."

He said the message sent by the four commissioners who disowned the results, was that "the chair of the commission does not have the authority to decide unilaterally the final results of the election".

Neither the chairman of the electoral commission, Wafula Chebukati, who declared Ruto the winner with 50.49% of the vote against Odinga's 48.5%, nor the four commissioners who disowned the results responded to a Reuters request for comment.

Ruto, the current deputy president and head of the Kenya Kwanza (Kenya First) Alliance, had appeared to be leading Odinga as Kenyans awaited final results of the election.

The four commissioners who disowned the election results also said the parties should seek resolution through the courts.

Businesses were open as normal in most of the country, and people in areas that voted overwhelmingly for Ruto were still in a celebratory mood.

Kenya, East Africa's richest and most stable nation, has a history of post-election bloodshed, with over 1,200 people killed in widespread violence after the 2007 presidential vote.

More than 100 people were killed after the Supreme Court overturned the result of the last presidential election in 2017 due to anomalies in the voting process.

-Reuters