The trial of Kenya’s Deputy President William Ruto has open at the International Criminal Court (ICC) in The Hague, Netherlands.
Mr Ruto and President Uhuru Kenyatta are accused of orchestrating violence after elections in 2007 – allegations they deny.
The ICC said their trials would not clash, after Mr Kenyatta warned that the constitution prevented the two men from being abroad at the same time.
He is due to go on trial in November.
The judges at The Hague have indicated the two cases could be heard alternately – in blocks of four weeks following a request by Mr Kenyatta that the two defendants should not be away from Kenya at the same time.
This is a politically controversial trial with a complex legal history, says the BBC’s Anna Holligan in The Hague.
In 2008, the United Nations was brought in to mediate.
The peace deal that brought an end to the brutal killings included an agreement that those responsible for the violence must be held to account.
The Waki Commission, set up to investigate the violence, recommended that if efforts to establish special tribunals in Kenya failed, the matter should be sent to The Hague.
Mr Ruto will be the first sitting government official to go on trial at the ICC, our correspondent adds.
Radio boss Joshua arap Sang has also been charged with inciting and helping co-ordinate attacks.
He will be tried alongside Mr Ruto. He also denies the charges.
The charges against the three stem from violence that broke out after disputed elections in 2007, in which more than 1,000 people were killed and 600,000 forced from their homes.
Mr Kenyatta and Mr Ruto were on opposite sides during the 2007 election and are accused of orchestrating attacks on members of each other’s ethnic groups, but formed an alliance for elections in March this year.
Analysts say the ICC prosecutions bolstered their campaign as they portrayed it as foreign interference in Kenya’s domestic affairs.
On Thursday, Kenya’s parliament passed a motion calling for Kenya to withdraw from the ICC.
The court said the cases would continue, even if Kenya withdrew.
The ICC was set up in 2002 to deal with genocide, crimes against humanity, war crimes and the crime of aggression.
BBC News Africa
