NAIROBI, Kenya (CNN) -- Kofi Annan has threatened to leave as mediator in the tense Kenyan power-sharing talks if a quick agreement is not reached, a senior aide to former U.N. chief said Monday.
Former U.N. Secretary-General Kofi Annan is the chief mediator in talks aimed at defusing Kenya's crisis.
Negotiating teams for Kenya's government and opposition left the talks after only half a day Monday. Sources close to the negotiations said the talks had reached a standstill
Annan, the former U.N. secretary-general and chief mediator in the process, expressed displeasure.
"After four hours of intense negotiation this morning, the team made almost no progress on reaching an agreement on government," Annan said in a statement. "I had to conclude that they were not capable of resolving the outstanding issues."
Annan met with leaders of both sides Monday to implore them to come to an agreement.
A senior aide said that Annan "believes that if genuine political will had prevailed, the problems could have been resolved a week or two ago. He has suspended a lot of important activities to help Kenya. And if this foot-dragging continues it is unlikely that he will be able to hang on."
Annan on Friday asked for both President Mwai Kibaki and opposition leader Raila Odinga to "give their negotiators clear instructions so that we can more swiftly to a conclusion," sources with Annan's team said. But sources close to the negotiations said there remained definite sticking points to finding a solution.
It was not immediately clear what those sticking points were.
Violence erupted in Kenya after the December 27 presidential election, when incumbent Kibaki of the Party of National Unity was declared victor. Odinga's backers said the election was rigged, and he and his supporters declined to recognize it as valid.
Both sides said Monday the government had agreed to the opposition Orange Democratic Movement's demand to have the prime minister's job. The powers of that post and details of its creation were under discussion.
The opposition party also has said it wants a proportional sharing of powers in any new government.
The opposition threatened last week to embark on a mass civil disobedience campaign by Wednesday if its demands were not met, employing such tactics as work slowdowns to apply pressure in the talks.
The fighting that followed December's election has broken down along tribal lines. Members of Kibaki's Kikuyu tribe and Odinga's Luo tribe have been in the middle of the ethnic clashes.
Both sides eventually agreed to talks and approved the creation of an independent committee to investigate irregularities in the election and suggest reforms.
But the opposition parliamentary group has been accusing the ruling party of "procrastination and obvious time buying games" at the talks. E-mail to a friend
CNN's David McKenzie contributed to this report.