Kenyan opposition figure Raila Odinga said Tuesday he’ll challenge the results of the close presidential election with “all constitutional and legal options” after Deputy President William Ruto was declared the winner, bringing new uncertainty to a country where the vote was widely considered to be its most peaceful.

Now East Africa’s most stable democracy faces weeks of disputes and the possibility that the Supreme Court will order a fresh election. Religious and other leaders have pleaded for calm in a country with a history of deadly post-election violence.

“Let no one take the law into their own hands,” Odinga said to his often passionate supporters. In Kisumu, a city in his western Kenya stronghold, some residents said they were tired of going into the street and being tear-gassed.

This was Odinga's first appearance since Kenya’s electoral commission chairman on Monday declared Ruto the winner with almost 50.5 percent of the votes. Four of the seven commissioners abruptly announced they couldn’t support the results, and Odinga supporters scuffled with the remaining commissioners at the declaration venue.

Shortly before Odinga spoke, the four commissioners asserted to journalists that the chairman’s final math added up to 100.01 percent and the excess votes would have made a “significant difference.” They also said he didn’t give them a chance to discuss the results before his declaration.

“What we saw yesterday was a travesty and blatant disregard of the constitution,” Odinga said, calling the election results “null and void.”

The 77-year-old Odinga has pursued the presidency for a quarter-century. His campaign has seven days after Monday's declaration to file a petition with the Supreme Court, which would then have 14 days to make a ruling. (AP)