Raila Odinga, a member of the opposition, stated on Tuesday that he would contest the results of Kenya's close presidential election using "all constitutional and legal options" after Deputy President William Ruto was declared the winner, bringing new uncertainty to the most stable democracy in East Africa.

Now the nation faces weeks of litigation and the prospect that the Supreme Court could order new elections. Religious and other groups have called for continued calm in a country with a history of lethal post-election violence.

"No one should take the law into their own hands," Odinga told his frequently fervent fans. In Kisumu, a city in his stronghold in western Kenya, some locals complained that they were tired of being tear-gassed when they went into the street.

It was Odinga's first appearance since the chairman of Kenya's electoral commission pronounced Ruto, the winner with about 50.5% of the vote on Monday. Four of the seven commissioners announced abruptly that they could not endorse the findings, and supporters of Odinga clashed with the remaining commissioners at the site where the results were revealed.

Before Odinga spoke, the four commissioners told journalists that the chairman's final calculations totaled 100.01 percent and that the additional votes would have made a "significant difference." They also said he did not allow them to discuss the results before his announcement.

"What we witnessed yesterday was a travesty and a flagrant disregard for the constitution," added Odinga, who declared the election results "null and void."

The president-elect described the commissioners' claims as a "sideshow" and stated that they have no bearing on the validity of the declaration. Monday's statement from the U.S. Embassy referred to the announcement as "an important step in the electoral process."

Odinga, 77, has sought the presidency for a quarter century. After Monday's statement, his campaign has seven days to file a petition with the Supreme Court, which would have 14 days to issue a verdict.

Odinga is recognized as a fighter and was imprisoned for several years in the 1980s due to his efforts to promote multiparty democracy. He also supported Kenya's revolutionary 2010 constitution.

His accusation that the tumultuous election of 2007 was stolen from him resulted in over a thousand deaths of bloodshed. Although he did not participate in the 2017 election, his legal challenge led to electoral reforms.

By releasing the more than 46,000 results forms from around the country online, the electoral commission was viewed as increasing its transparency in this election, enabling Kenyans to conduct the tallying themselves.

Tuesday, the local Elections Observation Group announced that their highly regarded parallel vote tally validated the official results in a crucial procedural audit.

However, Odinga said that the chairman unjustly kept the election results from the remainder of the committee until he had declared the victor. "The law does not grant the chairman dictatorial powers," he stated, insisting that the commission's conclusions must be reached by consensus.

The electoral commission or its chairman issued no immediate statement. The screen at its tallying center that displayed cumulative presidential election results ceased receiving updates on Saturday and was eventually switched off.

Odinga's campaign anticipated victory because outgoing President Uhuru Kenyatta backed his erstwhile opponent Odinga instead of his vice president, with whom he had feuded for years. Several Kenyans have pointed out that Kenyatta appointed the four opposing commissioners the previous year.

Ruto, the 55-year-old president-elect, appealed to Kenyans by framing the election in terms of economic disparities, as opposed to the ethnic ones that have long dominated the country's politics and occasionally led to deadly violence. He portrayed himself as an outsider from humble origins who challenged the political dynasties of Kenyatta and Odinga, whose fathers were Kenya's first president and vice president, respectively.

Despite this, just 65 percent of Kenya's 56 million eligible voters participated in last Tuesday's election, expressing frustration and lack of faith that the candidates would address the issues of rising costs, massive unemployment, and rampant corruption. The now-wealthy Ruto has denied several accusations of land grabbing and other forms of corruption.

Ruto's past includes an indictment for crimes against humanity by the International Criminal Court for his role in the 2007 election violence; however, the case was abandoned amid suspicions of witness coercion.

Kenya's outgoing president kept mute as an increasing number of African leaders made messages praising Ruto.