NAIROBI, Kenya -- The former head of the U.N. -- the man who helped save Kenya from spiraling deeper into election violence five years ago -- warned Saturday that intimidation, ethnic rivalry and violence could undermine Kenya's March 4 presidential vote.

Kofi Annan said that Kenya is on a positive trajectory five years after post-election violence killed more than 1,000 people and forced some 600,000 from their homes. But he reminded Kenyans that their country stood on the "precipice of self-destruction" after the country's last vote.

"The elections must be peaceful, free and fair. They must be conducted in accordance with the rule of law. They must be carried out with integrity, and must reflect the will of the people. Only then will national unity, stability and cohesion be safeguarded," Annan said in a statement.

"Yet, intimidation, electoral violence and ethnic rivalry have the potential to undermine and jeopardize the whole process," he added. "And that is why recent violent events and increasing tensions in the run-up to the elections are deeply worrying. Kenya cannot risk a return to those dark days."

Annan in early 2008 helped broker a political deal between the top two contenders for president. That deal saw Mwai Kibaki remain president and challenger Raila Odinga become prime minister. Kibaki is not running this year because of term limits; Odinga is one of two top contenders for president.

Annan told Kenyans in his statement that elections should not be viewed as a winner-take-all competition. He noted that Kenya has a new constitution and an improved judiciary, and he said the results of free and fair elections must be respected, and disputes settled through the courts.

Annan had been making regular trips to meet with top officials in Kenya in the hopes of helping avoid election violence, but the former U.N. chief has not visited in several months because some Kenyan leaders began to see those visits as outside meddling

The March 4 vote sees a raft of local, regional and national level races. But unless Odinga or his top challenger Uhuru Kenyatta wins at least 50 per cent of the vote, a run-off for president will be held, likely sometime in April. That vote holds even more potential for violence than the March 4 ballot, according to analysts.

Complicating this year's vote, Kenyatta faces charges at the International Criminal Court over allegations he helped orchestrate the 2007-08 election violence. Kenyatta and his running mate, William Ruto, are both due to attend a session at the ICC in mid-April, potentially right in the middle of the campaign for the second-round presidential vote. If Kenyatta and Ruto win, Kenya could face a situation where the country's president and vice-president must attend court sessions at The Hague while running the country.

The United States, France and Switzerland have said that their relations with Kenya are likely to change if Kenyatta is elected, because of the charges he faces at the ICC.

Kenya's elections are the most complex the country has ever faced, according to a report released Saturday by the London think-tank Chatham House. The ICC indictments of Kenyatta and Ruto have boosted their popularity among parts of the Kenyan electorate, said the report, but it added that the timings of the upcoming trials would "severely impede" the ability of the two to carry out their duties they were to win. The ICC court hearings could last several years.

The report concluded: "A more negative impact of the ICC's involvement is the way that it has raised the stakes of winning and losing the 2013 elections, and has contributed to the division of Kenyan voters into two opposing camps characterized by a strong ethnic logic."