Kenya's president called for calm Tuesday as violence in the east African country spiralled following the shooting death of an opposition MP outside his home.

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Armed with machetes and rocks, Kenyan men from the Luo tribe enforce a makeshift roadblock, searching passing vehicles for rival Kikuyus trying to flee Kisumu. ((Ben Curtis/Associated Press))

President Mwai Kibaki's office issued the plea hours after Orange Democratic Movement (ODM) MP Melitus Were was shot twice in the head at the gate of his suburban Nairobi home shortly after midnight. 

"The president appeals to all Kenyans to maintain peace," said the statement.

Raila Odinga, who heads the opposition ODM, warned Kenya "is drifting into a state of anarchy."

Violence erupted in the Nairobi slum of Kibera hours after Were's death, with as many as seven people killed during the clashes, said Reuters. A witness claimed to see two corpses on the ground, while another man was in critical condition after reportedly being circumcised against his will and cut in the leg, according to Reuters. Circumcision is a rite of passage practised by most Kenyan tribes, but not Luos.

"There are groups attacking each other with bows and arrows," a Kibera resident was quoted as saying.

In the city of Naivasha, two Kenyan military helicopters fired rubber bullets at a mob of about 600 people threatening refugees from a rival tribe, said reports. It happened as police were trying to move the 300 Luo refugees from the area.

It's not clear if anyone was injured.

Annan opens mediation

More than 800 people have been killed in fighting that began shortly after Kibaki declared victory in a contested December vote.

International and local election observers have said there were significant problems with the election, while Odinga's supporters have made accusations of rigging.

Former United Nations secretary general Kofi Annan, who opened formal mediation talks Tuesday in the capital, said he expects Kenya's "immediate political issues" to be resolved within four weeks.

"There is only one Kenya. The crisis has a profound and negative impact on the social fabric of Kenya, on the Kenyan economy," he said.

"We are confident that the issues can be resolved within a year … and the immediate political issues can be resolved within four weeks if not shorter."

Mourners gather at MPs house

Police fired tear gas on Tuesday morning to disperse a group of mourners and supporters who had gathered at Were's house and taunted officers.

Police said they are treating the opposition MP's death as a homicide. They said politics has not been ruled out as a motive for the slaying, which occurred in the middle-class Woodley Estate district just after midnight.

"We are treating it as a murder, but we are not ruling out anything, including political motives. We are urging everyone to remain calm," Kenya police spokesman Eric Kiraithe said.

Representing Nairobi's Embakasai district, Were won a seat in the Dec. 27 legislative election held alongside the presidential vote, according to a report by the BBC. He is the first major politician to be killed during post-election violence in Kenya.

His district includes the Dandora slum, a stronghold of a feared Kikuyu gang known as Mungiki.

ODM spokesman Tony Gachoka is quoted by the BBC as saying: "The current situation makes one suspicious. All fingers will point at the government, and the government will have to show it is not involved."

Horrifying scenes of violence

Elsewhere in the country, the scene was equally gruesome.

Youths armed with machetes were on a murderous hunt for members of Kibaki's Kikuyu tribe in western Kenya's Rift Valley.

"The road is covered in blood. It's chaos. Luos are hunting Kikuyus for revenge," said Baraka Karama, a journalist for independent Kenya Television in Kisumu.

In the central towns of Nakuru and Naivasha, five days of rioting have left dozens of people dead and many more on the move as residents search for refuge from the violence.

More than 255,000 people have been driven from their homes this month.

With files from the Associated Press