Kenya on Wednesday warned it would act tougher to rein in post-election violence threatening to spiral out of control in the east African nation's darkest moment since independence in 1963.
Protests over President Mwai Kibaki's disputed re-election in the December 27 election have degenerated into cycles of killing between rival tribes, and there is increasing evidence of gangs being well organised on both sides.
The top US diplomat for Africa urged the political rivals to forge a compromise at mediation led by former UN chief Kofi Annan and warned that the cycle of ethnic retaliation had "gone too far".
"There has been an organised effort to push out people from Rift Valley ... It is clearly ethnic cleansing," U.S. Assistant Secretary for African Affairs Jendayi Frazer said in Ethiopia.
Most of the deaths since the election came in attacks that at first targeted Kibaki's Kikuyu tribe.
They are now taking revenge on pro-opposition tribes.
Police have also killed close to 100 protesters backing opposition leader Raila Odinga.
Internal Security Minister George Saitoti on Wednesday warned that police would tolerate no more violence, and would ensure that Kenya's roads and rail lines -- critical lifelines for neighbouring nations -- would remain open.
"We have decided to act tough this time. We are not going to allow criminals and hooligans to run around. No country or government can allow that," he told reporters.
Angry youths have set up roadblocks all over the Rift Valley in the past month, squeezing transport into neighbouring Uganda, Rwanda, Burundi and South Sudan and hurting their economies -- dependent on Kenya's Mombasa port.
The government on Tuesday demonstrated its willingness to apply heavier force, sending in two army helicopters to strafe a Kikuyu mob with rubber bullets in Naivasha. Saitoti said the military would still be used in a humanitarian capacity.
More than 250,000 people are living as refugees.
Some Kenyans laid wreaths at Nairobi's "Freedom Corner" on Wednesday. "Peace", "Love", "Sorry" read some cards with them.
Annan's team on Thursday plans a second day of talks between Odinga and Kibaki's negotiators, each a mix of moderates and hardliners -- the latter of whom are blocking progress.
'We're not brothers'
Annan, after bringing Kibaki and Odinga together on Tuesday, said he was confident "immediate political issues" could be resolved in four weeks. Broader issues could take a year.
Kibaki, 76, says he is the legally elected president, but is open to sharing power. Odinga, 63, says he was robbed by fraud during the vote count and wants Kibaki to stand down or allow a new election after a period of power-sharing.
Much hangs on the fate of the talks, including the future of Kenya's economy -- east Africa's largest and previously one of its brightest. The $1 billion a year tourism industry has been hard-hit and the currency is near a three-year low.
The Kenya Association of Manufacturers warned gross domestic product could fall by 3 percent if violence doesn't stop.
Just north of Nairobi in Nderi, a group of unarmed Kikuyus cornered people from the rival Luo tribe inside the Kenya Forestry Research Institute. "We were living here as brothers but we have now come to realise that we are not," said Frederick Muiruri, part of the Kikuyu group outside.
More than 100 people have been killed in the Rift Valley towns of Nakuru and Naivasha since Thursday, mostly as Kikuyus avenged attacks on their kin in other parts of the Rift that started moments after Kibaki was sworn in on Dec. 30.
Inter-ethnic killings also have hit Nairobi's slums.
The violence has taken the lid off decades-old divisions between communities over land, wealth and power that hark back to British colonial rule and have been stoked by politicians at election time over 44 years of independence.
(Additional reporting by Joseph Sudah, Bryson Hull, Jack Kimball and Duncan Miriri; writing by Bryson Hull; editing by Andrew Cawthorne and Giles Elgood)