|PIC1|Kenyan police and opposition backers clashed on Thursday in a second day of protests against President Mwai Kibaki's disputed re-election in which police have already killed three.

Riot police fired teargas at hundreds of supporters of opposition challenger Raila Odinga and his Orange Democratic Movement (ODM) coalition, blocking a road near Nairobi's Mathare slum, witnesses said.

Reuters photographer Antony Njuguna said about 40 police officers were facing off with hundreds of demonstrators near Mathare, one of the flashpoints during nearly three weeks of violence that has convulsed the east African nation.

"There's a massive crowd trying to block the road. Police are shooting teargas at them," he said from the scene.

In the western opposition stronghold of Kisumu, riot police shot in the air and struck at least one man as they battled youths who set up blazing roadblocks and gathered to protest.

"My father was shot as he stood in front of our house. The police were shooting indiscriminately, targeting anyone on sight. My father was shot in the stomach," witness Alphonse Otieno said by phone from Kisumu's Kondele slum.

Kisumu saw the worst violence on Wednesday, the first of three days of nationwide demonstrations called by the opposition.

Police have banned the rallies called by Odinga, who says Kibaki stole the December 27 election. The government in turn accuses his side of rigging votes and of protesting instead of using legal options to challenge the result.

Kenya's sudden descent into crisis has tarnished its democratic credentials, horrified world powers, scared off tourists and hurt one of Africa's most promising economies.

Police have met the latest unrest with tear gas and live ammunition as they did in earlier protests which ground the east African nation to a halt, delaying school openings and shutting businesses.

On Wednesday, police shot dead three in Kisumu - which erupted in a spree of looting and rioting immediately after Kibaki was sworn in on December 30.

ODM spokesman Salim Lone condemned one killing, captured on television, as a "cold-blooded execution."

In footage shown by local broadcaster KTN, a Kisumu policeman was seen firing his assault rifle at a young man who fell down, and then was kicked by the officer.

KTN, which said four people were feared killed on Wednesday, said the youth later died. Police spokesman Eric Kiraithe told media those shot in Kisumu had attacked officers first.

'TWO BULLS FIGHT'

Also on Wednesday, TV footage showed police tear-gassing opposition leaders at two hotels, and then chasing them down Nairobi's main Kenyatta Avenue. Odinga was near but stayed in his four-wheel drive truck, the footage showed.

Human Rights Watch said police have been heavy-handed and have killed at least 47 people during the post-election turmoil.

Around 620 have been killed nationwide in attacks on tribes and people suspected of having supported Kibaki, and by police.

A quarter of a million people, many of them members of Kibaki's Kikuyu ethnic group, have been forced from their homes.

International observers have said the vote fell short of democratic standards and both sides accuse the other of rigging.

The United States and former colonial power Britain have called on Kibaki's government to let peaceful protests go ahead.

They and 11 other nations have threatened to cut aid if the government's commitment to "good governance, democracy, the rule of law and human rights weakens".

But those are likely empty threats because Kenya gets less than 5 percent of its budget from donors.

The Nation newspaper urged both sides to "isolate dangerous demagogues" in their midst to forge a compromise to save Kenya.

"When two bulls fight ... it is the grass that suffers. The grass here is the ordinary people of Kenya who have been reduced to expendable cannon fodder as the rich and powerful duel for political supremacy," the paper said in an editorial.

Since being sworn in, Kibaki, 76, has entrenched his position by naming most of a new cabinet, including figures the ODM says are hardliners, and calling parliament to meet.

Former U.N. boss Kofi Annan had been due in Kenya this week to lead a team of "Eminent Africans" in a push for peace, but he fell ill. His office gave no date for his arrival.