NAIROBI, Kenya — The spark for Kenya's firestorm of ethnic violence was lit inside a cavernous meeting hall in downtown Nairobi , where election officials over four days doctored vote counts, dismissed eye-popping irregularities and thwarted monitoring by independent observers to deliver a razor-thin victory to President Mwai Kibaki .

Observers who were allowed into the vote-tallying center on Dec. 29-30 , hours before the results were announced, said there was so much systematic fraud by Kenya's government-appointed election commission that it's impossible to know who really won.

The extent of the commission's deceptions has faded into the background as more than 800 Kenyans have been killed in ethnic clashes and police crackdowns. The events also have deeply unsettled the Bush administration, which has relied on Kenya as an ally in the war on terror and a bulwark of stability in East Africa .

Official results gave Kibaki an edge of 231,728 votes, or 2 percent, out of about 10 million cast. Initial results of an exit poll by the U.S.-funded International Republican Institute found that rival Raila Odinga had won by an 8 percent margin.

Election officials allowed five accredited Kenyan observers into the tallying center in Nairobi only in the final phase of vote-counting, and three of them shared their accounts with McClatchy. All said that the gravest cheating occurred in that room, where commissioners— all appointed by Kibaki— compiled returns before announcing them to the public.

The observers spoke in interviews and quoted from a joint log of their experiences, titled "Countdown to Deception," which Kenyan rights groups are circulating.

The long-serving chairman of Kenya's election commission played an active role in the deception, the observers said. When a tallying officer presented results showing voter turnout at 115 percent in Maragua, a Kibaki stronghold in the central highlands, commission Chairman Samuel Kivuitu didn't invalidate the result as required by law, but allowed a commissioner to reduce the figure to 85 percent and announced the results an hour later.

That was the pattern that observers reported: Results were announced even when documents were missing, incomplete, unsigned by officers or party representatives, incorrectly tabulated, photocopied or forged.

"Both sides stole votes," said Julius Melli , a 31-year-old Kenyan radiographer who witnessed the tallying of Maragua and other locales. "But Kibaki stole more, and they stole it inside the tallying center."

The Electoral Commission of Kenya , an independent body whose members are appointed by the president, had run national elections in 2002 and 2005 that were praised for their openness and accuracy.

But except for Kivuitu, who'd served as chairman since 1997, this was a largely different commission. As members faced term limits in the months before the vote, Kibaki— facing the stiffest presidential challenge ever in Kenya — packed the 22-person body with 17 new commissioners. All were considered Kibaki allies, and none had ever run an election.

"These people were criminals," said Ben Sihanya, a Stanford -educated constitutional law professor who also observed the tallying. "They were committing crimes at the behest of Kibaki's government."

Election officials were unreachable for comment, but the commission has taken out a two-page, unsigned advertisement in Kenyan newspapers to deny wrongdoing.

Koki Muli , the co-chair of the Kenya Domestic Observers Forum , suspected problems soon after the polls closed on the evening of Dec. 27 . Her network of observers monitoring the vote-counting in polling stations immediately began sending preliminary results by phone and text messages. But for two days, in the Nairobi convention hall where the election commission had set up shop— surrounded by hundreds of journalists, observers and party agents— Kivuitu announced only some of the returns.

Observers grew suspicious when results from Kibaki's central Kenya stronghold weren't read. The delays were sparking protests. "It was necessary for us to observe the tallying," Muli said.

For 48 hours, armed agents barred observers from entering the tallying center, a high-ceilinged room almost the size of a football field. Finally, faced with mounting reports of irregularities, Kivuitu allowed five observers and a handful of political party representatives into the room on the night of Dec. 29 . They were greeted with nervous stares.

"What I saw in that room alarmed me," Muli said. "It was a very scared staff."

Commissioners and staff members were seated around a dozen or so long tables, each strewn with folders containing the legal forms required to certify vote counts. In one corner of the room, a bank of computers churned out results and printouts.

The lanky, bespectacled Sihanya walked up to a table and introduced himself to commissioner Mildred Owour . "Can we sit at your table?" he asked.

"You are going to slow down the process," she replied.

At about 10 p.m. , Sihanya, Melli and two other observers sat down with agents of the main political parties and several commissioners and election officials. Their task was to scrutinize irregularities reported by Odinga's camp— and there were many.

In at least 44 out of 210 constituencies, officials in Nairobi had announced vote totals without any supporting documents from the polling centers. In most places the announced totals were off by hundreds or thousands from what journalists, party agents and foreign observers had witnessed at polling places.

The team prepared to work through the night. When commission staff members brought a stack of folders, observers asked to check whether vote totals had been added correctly.

The commission's legal officer, Jemimah Kelli , rebuffed them.

"She said, 'We can't correct the tallying now. The commission will take care of it,'" Sihanya recalled.

At another table, Muli was scratching her head over results from Mathira, in central Kenya , where nearly everyone voted for Kibaki. Election officers had failed to sign the tallies from nearly three dozen polling places, and one form had two different totals. Muli took out her cell phone and began adding up the numbers.

She calculated 77,442 votes for Kibaki, some 2,600 fewer than what was recorded on the final tally sheet and announced to the public. Later she discovered inflated vote totals for Kibaki in several other areas— "3,000 here, 3,000 there, 1,500 here, 2,500 there," she said. "It added up."

At his table, Melli saw numerous constituencies that lacked tally sheets or official signatures, but whose results had been certified anyway. In one folder, he found two tallies for the same place— one a signed original, the other an unsigned photocopy that had been altered to give Kibaki about 3,000 more votes.

The photocopied version had been used.

"It looked very ridiculous," Melli said. But Kenyan election laws didn't authorize observers to do anything more than note inconsistencies.

The legal officer, Kelli, moaned that officials had gone without sleep for several days, and she harassed Melli for paying too much attention to detail.

"She told Melli, 'You seem to be very keen. Are you being paid to do this?'" Sihanya said. (They in fact were not paid.)

When Sihanya questioned inconsistencies in one Kibaki stronghold, a Kibaki party representative, Martha Karua, accused him of being an opposition agent.

"The whole thing seemed extremely stage-managed," Melli said. "It was not a sincere verification exercise."

As the night wore on, officials became cagier. Melli asked an official for the file from Nithi, where turnout was a suspiciously high 80 percent and nearly all the votes had gone to Kibaki. The official blanched, pulled the file close to his chest and, for the rest of the night, carried it with him everywhere he went, Melli said.

The file for Kieni in central Kenya showed 87,500 parliamentary votes— nearly 3,000 more than the number of registered voters. The file for Imenti South district, where Kibaki had 96 percent support, showed 4,315 more presidential votes than parliamentary votes but contained no supporting documents. At 5 a.m. on Dec. 30 , the file for another central district, Molo, finally appeared showing 50,145 votes for Kibaki. The chairman later announced 75,261.

"They just gave Kibaki 25,000 votes from the air," Muli said.

Finally, at around 9 a.m. , Karua, the Kibaki aide, said the verification had to be halted so that the commissioners could get "back to work." An Odinga aide said he had concerns about other files, but Karua and three election officials at the table stood up to leave.

One of the commissioners, Luciano Riunga Raiji, told the observers, "You are done." Shortly afterward, a message blared over the loudspeaker ordering all observers and party agents to leave the room. By then, Melli said, it was clear that the commissioners had no intention of investigating the irregularities.

"We were waiting for them to announce the final results," he said. "But we knew Kibaki had stolen it."

Muli, who's helped train commissioners for 14 years, said: "We didn't imagine that the electoral commissioners could in a massive way influence the conduct of the election. We were wrong."

The next several hours were surreal, the observers said. As word swept through the convention hall that Kibaki would be declared the winner, Odinga called a news conference and accused the commission of rigging the vote in 48 constituencies.

A few hours later, the opposition trotted out an election staffer, Kipkemoi Kirui, who said that officials were manipulating results at the tallying center. "My conscience could not allow me to see what I was seeing and keep quiet," Kirui told reporters. He's now fled the country, according to media reports.

An hour after that, the lights went off in the convention hall, and paramilitary police cleared the building. In a sealed room, the election chairman announced Kibaki's victory on state television. Within minutes, rioters were tearing through the streets of Nairobi .

Kenya's nightmare had begun.

(Special correspondent Munene Kilongi contributed.)