Luis Moreno Ocampo said he told President Mwai Kibaki and Prime Minister Raila Odinga he will ask a pretrial chamber in December to allow him to formally open an investigation into the violence that took place between December 2007 and February 2008 after a contentious presidential election.

"I consider the conflict in Kenya a crime against humanity and I consider, therefore, the gravity is there, and so therefore I should proceed," Moreno Ocampo said. "So I informed them in December I will request to the judges of the International Criminal Court to open an investigation."

Kibaki and Odinga said at the same news conference that the government will fully cooperate with the ICC.

"We are ready and willing to work and cooperate with Mr. Ocampo to ensure that those who bear the responsibility for the crimes that were committed are brought to justice," Odinga said.

Moreno Ocampo's office has been evaluating whether the Kenyan violence constituted crimes against humanity since January 2008. In July this year, former U.N. chief Kofi Annan, who mediated an end to the violence, sent Moreno Ocampo a sealed envelope with the names of suspected ringleaders.

An independent commission that investigated the postelection violence came up with the names and chose to keep them secret, saying they are powerful individuals who could interfere with future investigations. The commissioners placed the names in an envelope and gave it to Annan along with supporting evidence.

The commission had recommended to the government that it form an independent tribunal with Kenyan and foreign judges to try the suspects, arguing that Kenyan courts are not credible. Failing that, it recommended the ICC take over the cases. Both recommendations won wide local and international support.

The government has so far failed to form an independent tribunal, drawing criticism from ordinary Kenyans and diplomats.

The violence came after rival campaigns disputed the results of the December 2007 presidential election. Several human rights bodies blamed businessmen and politicians in the current administration for orchestrating the violence, which was the worst since Kenya gained independence from Britain in 1963.

The clashes severely damaged Kenya's reputation _ the region's largest economy had long regarded as a haven of stability in a region roiled by brutal civil wars. Tourism, the country's second largest foreign exchange earner, declined in its wake. Problems with corruption and extrajudicial killings by the security forces have not been addressed.

Kibaki and Odinga signed a power sharing deal in February 2008 to end the violence. The deal also detailed wide-ranging reforms seen as essential for Kenya to avoid future violence.