Kenya is to have general elections in March.
The International Criminal Court in January charged four high-ranking Kenyan officials with crimes related to conflicts that erupted after disputed 2007 elections. More than 1,000 people were killed in fighting between supporters of incumbent President Mwai Kibaki against those of rival Raila Odinga.
Deputy Prime Minister Uhuru Kenyatta and former Education Minister William Ruto were among those charged by the court. Both men said they plan to run on the same ticket next year with Kenyatta vying for the presidency.
Former U.N. Secretary-General Kofi Annan, serving as an AU envoy to the election, told the BBC that voters shouldn't support leaders who can't attract global recognition.
"When you elect a leader who cannot do that, who will not be free or will not be easily received, it is not in the interests of the country and I'm sure the population will understand that," he said.
Annan didn't single out Kenyatta or Ruto. Both leaders denied involvement in post-election violence in 2007.
"The ICC cases have formed the basis of debates but we are going to prove them wrong (and show) that Kenyans are united and want peace," Ruto was quoted as saying during a rally this week.