In a report, "'They Beat Me like a Dog': Political Persecution of Opposition Activists and Supporters in Zimbabwe," the New-York based rights group accused the ruling ZANU-PF and its supporters of killings, beatings and arbitrary arrests of opposition MDC members of parliament and activists.

It urged the Southern African Development Community (SADC) group of countries to take a tough stand against the alleged abuses at its Aug. 16 summit in South Africa.

Human Rights Watch said SADC should ensure that Zimbabwe's police "immediately dismantle all torture camps and bases throughout the country and prosecute those responsible for torture and other mistreatment".

Chief Zimbabwe mediator, South African President Thabo Mbeki, who takes over the SADC chairmanship at the summit, has been trying to persuade President Robert Mugabe and opposition leaders to reach an agreement in make-or-break talks in Harare.

Zimbabwe's ruling party warned power-sharing talks resuming on Tuesday risked collapse as it haggled with the opposition over roles in a new government.

The talks are seen as the best chance to end a post-election crisis and raise hopes of economic recovery.

"ZANU-PF and its allies are still committing violent abuses, undermining the party's credibility as a political partner," said Georgette Gagnon, Africa director at Human Rights Watch.

"Instead of focusing on quick political fixes, President Thabo Mbeki and other SADC leaders should look for a durable solution, and that means, first of all, an immediate end to human rights violations."

Mbeki has dismissed repeated calls to take a tough stand against Mugabe, saying this would only aggravate tensions and undermine efforts to reach a settlement.

In one example of violence, the report said a 70-year-old woman who was assaulted witnessed the killing of her son, Gibbs Chironga, an MDC councillor, by ZANU-PF militia on June 20.

"I am an old woman and they beat me like a dog, no, a wild animal. They insulted me; they beat me on the back and in the ribs. My only crime was that my son was an MDC councillor," Human Rights Watch quoted her as saying.

"I am in great pain. Now my son is in the mortuary, I am unable to bury him. I will not be there when he is buried, if he is buried. I regret being alive. My life is ruined, my home is destroyed and my son's life was taken in cold blood."