“For the first time in the history of African democratization, a ruling has been made by a court nullifying the election of a president,” he said. “This indeed is a very historic day for the people of Kenya and by extension the people of the continent of Africa.”

In a televised address to the nation, Kenyatta said he disagreed with the court’s ruling but would respect it.

“I disagree with it because as I’ve said, millions of Kenyans queued, made their choice, and six people have decided that they will go against the will of the people,” he said.

Kenyatta said his primary message was for all Kenyans to keep the peace. “Your neighbor will still be your neighbor regardless of whatever has happened,” he said. “Regardless of their political affiliation, regardless of their religion, regardless of their color, regardless of their tribe.”

As news of the court’s decision spread, cheers and celebrations could be heard on the streets in parts of the capital, Nairobi.

But it’s not yet clear if the ruling will spark public protests.

Although Kenya’s 2013 election was mainly peaceful, the country plunged into widespread violence in the aftermath of the 2007 vote. More than 1,000 people were killed in months of bloodshed after Odinga — defeated by then-President Mwai Kibaki — claimed the vote was rigged.

After Kenyatta was declared the winner last month by 54% to 45% for Odinga, sporadic violence erupted in some areas, claiming the lives of at least 24 people nationwide.

Odinga is a longtime challenger for the presidency who has yet to claim the country’s top office. Kenyatta, the 55-year-old son of the country’s founding President, has already served one five-year term.

Kenyatta lawyer: ‘Very political decision’

Kenyatta’s lead counsel, Ahmednassir Abdulahi said in court that his client wanted to see the full judgment to understand how the alleged irregularities would “obliterate” his 1.4 million vote winning margin.

“My lord it’s obvious, and I’m not afraid to say, that this is a very political decision you have made this morning but we will live with the consequences,” Abdulahi said. He added that the will of the people would prevail.

The Supreme Court has seven members but can conduct proceedings as long as five judges are present. Six judges participated in Friday’s ruling.

In his address after the ruling, Odinga railed against the national election body, the Independent Electoral and Boundaries Commission.

“We have no faith in the electoral commission as currently constituted,” Odinga said. “They have committed criminal acts. Most of them actually belong in jail and therefore we are going to ask prosecution for all the electoral commission officials who have committed this monstrous crime against the people of Kenya.”

He added: “This is a triumph for the people of Kenya.”

The chairman of the Independent Electoral and Boundaries Commission, Wafula Chebukati, later told reporters that the commission wanted to see the full judgment but that he had no plans to step down.

“The focus of the decision is in the transmission of presidential results, therefore there were no aspersions cast on the voting and counting of votes and that the sovereign will of the Kenyan people was fully respected in this respect,” he said.

Chebukati said the commission was committed to ensuring that the new election “is done in accordance with the constitution, the relevant laws” and urged the prosecution of any staffer found to have broken the law.

“The commission urges all Kenyans to remain calm and restrain themselves from any political rhetoric that may undermine the stability and cohesion of our country,” he added.

Rights group Amnesty International’s country director Justus Nyang’aya said the “ruling demonstrates the independence of Kenya’s judiciary and sets an example for the rest of the world.”

He added: “We urge all parties to comply with the judgment, and call on the police to observe restraint in their handling of any celebrations or protests that may follow this landmark ruling.”

Election monitors

Most of the demonstrators in last month’s post-election were supporters of Odinga, who had called the vote rigged. National election officials dismissed the accusations, however, saying the vote was free and credible.

More than 400 international election monitors were also deployed across the country to monitor voting, the tallying process and the post-election period.

Former US Secretary of State John Kerry, who served as an election observer for the Carter Center, said then that while there were “little aberrations here and there,” the election was not rigged.

Any unrest in Kenya could have ripple effects far beyond the nation of 47 million people.

As the largest economy in East Africa, Kenya is a crucial trade route to the continent and provides an important buffer of stability in a region that includes the fledgling Somali government and the politically tense Sudan and South Sudan.

Heavy selling

Trading on Kenya’s stock exchange, the Nairobi Security Exchange, was briefly suspended following the ruling but has since resumed.

“There was heavy selling, prices were coming down, there was a level of panic selling in that limited time,” said its chief executive, Geoffery Odundo. “This outcome people are yet to digest what it means. We have no precedent so investors are a bit cautious. Now we are seeing some level of calm.”

Odundo said he did not plan to halt trading again. “It’s more now how the messaging from the prospective leaders comes out. I suspect everyone is going to follow the law and the constitution,” he said.

A spokesman for the Nairobi Security Exchange, Kuria Waithaka, earlier told CNN: “People are jubilant, the rule of law has been upheld.”