Human Rights Watch reported Thursday that thousands of victims of Zimbabwe's brutal demolition of homes and markets last summer are still sleeping in the open, amid rubble, with little access to food or medicine.

The rights group, based in New York, blamed both the obstruction by Zimbabwe's government under President Robert Mugabe and the failure of U.N. agencies to insist on access to victims of a campaign that left 700,000 homeless, jobless or both.

"Many of them are living in terrible conditions," Tiseke Kasambala, a Human Rights Watch researcher, said at a news conference here. "It's an appalling situation."

U.N. officials acknowledged that their initial response was slow because of official resistance but said the report failed to take into account a recent expansion in humanitarian aid, including food and plastic shelters.

"We have much more access to the people than we had before," said Roeland Monasch, a UNICEF official in Zimbabwe, speaking from the capital, Harare. He said the agency had distributed plastic sheeting for up to 6,000 homeless families over the past two months.

During Operation Murambatsvina, which means "Drive Out the Rubbish" in Zimbabwe's Shona language, police marched through poor areas and ordered residents to tear down their homes. Police also raided informal markets that were among the country's few remaining havens of economic activity.

The demolitions, which started in May, ended in July after U.N. investigators detailed the destruction in a report. Mugabe has since announced a reconstruction effort, but Human Rights Watch said it has amounted to little. Many victims, the report says, found themselves harassed until they moved back to rural areas.

The rights group said that U.N. officials were prohibited from erecting tents or distributing food because Mugabe sought to hide the extent of the devastation.