NAIROBI, Kenya - The opposition called Friday for three days of rallies to protest Kenya's disputed presidential election, igniting fears of more deadly violence. Police said they would not allow the demonstrations.

The calls for rallies in 28 places across the East African nation came after days of international mediation failed to break a deadlock between President Mwai Kibaki and Raila Odinga, who came in second after a tally foreign observers say was rigged.

Now, it seems, the opposition sees little recourse other than taking to the streets.

"Kenyans are entitled to protest peacefully at this blatant violation of their fundamental rights," said Anyang Nyongo, secretary-general of Odinga's Orange Democratic Movement. Rallies were planned for Wednesday, Thursday and Friday.

Nyongo also called for economic sanctions, saying it would be irresponsible for international donors to "trust this government with a single cent which is going to be used to oppress the people and to perfect the art of stealing both the vote and our national resources."

Police, citing a government ban on rallies in the wake of the Dec. 27 election, said the protests would not be allowed. Police and opposition supporters have clashed in previous attempts to demonstrate, with security forces firing tear gas, water cannons and live bullets over people's heads.

More than 500 people have died in protests and ethnic violence since the election.

"We should reject violence and calls for demonstrations that do not improve our livelihoods but sustain political mischief of a few people," government spokesman Alfred Mutua said.

Human rights activists who have denounced the police for alleged unjustified killings and excessive force said Friday they had information some officers were plotting to harm them. Police spokesman Eric Kiraithe said the charges were "lies."

Diplomatic moves to diffuse the crisis quieted Friday with the State Department announcing the departure of leading Africa diplomat Jendayi Frazer. State Department spokesman Tom Casey told reporters the United States would continue to work toward a solution. He said Washington hoped any demonstrations would be peaceful and that the leaders would resolve their differences.

Former U.N. Secretary-General Kofi Annan has agreed to take over mediation but is not expected in Nairobi before Tuesday, his office in Geneva said. The chairman of the African Union, Ghanian President John Kufuor, left Thursday after failing to persuade Kibaki and Odinga to agree to meet.

Odinga has said he would meet Kibaki only in the presence of an international mediator. Kibaki wants direct talks.

The European Union, the United States and Britain also have been pressing for Kibaki and Odinga to meet.

Kenya is crucial to the U.S.-led war on terrorism, having turned over dozens of people to the United States and Ethiopia as suspected terrorists. It also allows American forces to operate from Kenyan bases and conducts joint exercises with U.S. troops in the region. The U.S. is a major donor to Kenya, long seen as a stable democracy in a region that includes war-ravaged Somalia and Sudan. Aid amounts to roughly $1 billion a year, the U.S. Embassy said.