A major UN report has called for an immediate end to Zimbabwe's slum clearance programme, declaring it to be in violation of international law.
Thousands of 'illegal' homes have been destroyed
"The scale of suffering is immense," it said. About 700,000 people have lost their homes or livelihoods and another 2.4 million people have been affected.
Secretary General Kofi Annan said it confirmed "catastrophic injustice" had been done to Zimbabwe's poorest.
But Zimbabwe said the allegations in the report were "definitely false".
Foreign Minister Simbarashe Mumbengegwi told journalists in the capital Harare the report showed an "in-built bias" and had described the clearances "in vastly judgmental language".
The BBC's Susannah Price at UN headquarters in New York says the UK and US are likely to use the hard-hitting document to renew their calls for the UN to take immediate action.
To date, the Security Council has refused to call a meeting on the clearances.
Zimbabwe's President Robert Mugabe usually rejects any criticism as coming from racists - or their stooges - opposed to his nationalist stance, but correspondents say this will be more difficult with this report.
Zimbabwe says the policy - known as Operation Murambatsvina [Drive Out Rubbish] - is intended to crack down on black-market trading and other criminal activity in the slum areas.
Hundreds of thousands of homes in the country's shanty towns have been torched and bulldozed in recent months.
The report was compiled by Kofi Annan's special envoy Anna Tibaijuka, an international diplomat from Tanzania, a country with close political links to Zimbabwe.
The Zimbabwean government's programme was carried out in "an indiscriminate and unjustified manner, with indifference to human suffering," the report said.
"The scale of suffering is immense, particularly among widows, single mothers, children, orphans, the elderly and disabled persons," it said.
"The international community should encourage the government to prosecute all those who orchestrated this catastrophe and those who may have caused criminal negligence leading to alleged deaths," the report said.
But it said the government was collectively responsible.
Mr Annan called on the Zimbabwean government to stop the forced evictions and demolitions immediately "and to ensure that those who orchestrated this ill-advised policy are held fully accountable for their actions".
The Zimbabwean opposition says the evictions are meant to punish urban residents, who have rejected Mr Mugabe in favour of the opposition in recent elections.
Among other things, Ms Tibaijuka recommended that Zimbabwe should:
- urgently launch a broad humanitarian aid campaign to help those evicted
- revise its outdated housing and planning laws
- set up a compensation fund to help restore a climate of trust and dialogue with the people
- take steps to reform its economy.
Mr Annan said the UN would urgently seek agreement with Zimbabwe "to mobilise immediate humanitarian assistance on the scale that is required to avert further suffering".
He urged the international community to respond "generously".