Former Kenyan Prime Minister Raila Odinga, who lost the Aug. 9 presidential elections by a tiny margin, rejected the outcome of the vote and vowed to take constitutional steps to challenge it.

Odinga, 77, who was making his fifth run at the presidency and secured 48.9% of the vote to Deputy President William Ruto’s 50.5%, said the head of the electoral commission didn’t follow due process, rendering the results declared “null and void.”

Odinga’s statement came a day after four of the nation’s seven electoral commissioners said they didn’t accept the outcome, because the process was handled in an “opaque” way.

On Tuesday, the Election Observer Group, which comprises 5,000 local monitors from civil rights and religious organizations, said the official count from the Independent and Electoral Boundaries Commission was consistent with its parallel tally, and the constitution gave the body’s Chairman Wafula Chebukati the right to declare the results.

Ruto, 55, said the IEBC had “bent over backward to accommodate everybody,” the election results spoke for themselves and their validity was being questioned by those who didn’t want to accept that they had lost.

“The people of Kenya have spoken and we need to respect what they have said,” he told reporters in Nairobi after he was declared the president-elect.