Human rights organizations are warning that the violence in Zimbabwe could spiral out of control and are calling for Southern African leaders to take action if the Zimbabwe government fails to halt the brutality. Correspondent Scott Bobb reports from our Southern Africa Bureau in Johannesburg.

A researcher for Human Rights Watch, Tiseke Kasambala, said in Johannesburg that the situation in Zimbabwe has worsened considerably since her visit six months ago.

"The level of repression was definitely higher," she said. "There was definitely more political tension in the air. People are tired of what is going on. Something has got to give. This kind of violence cannot just continue."

Tensions have been heightened in Zimbabwe since a police crackdown began nearly three weeks ago. Several-dozen opposition leaders were detained and beaten for trying to hold an anti-government rally. Opposition leaders say that many others have since undergone similar ordeals.

The government says the opposition is behind a series of gasoline (petrol) bombings and accuses it of trying to destabilize the country. Opposition leaders deny the charges.

Kasambala condemned the recent bombings and called for the perpetrators to be brought to justice. But she said abuses by security forces are the primary cause of the violence.

She said authorities are no longer just targeting opposition and civic leaders, but are now arresting and beating members of the general public.

Another human rights group, Amnesty International, expressed outrage Wednesday over what it called the brutal harassment, torture and intimidation of opposition activists.

Both human rights groups urged southern African leaders attending a summit in Tanzania to take a strong position against the aggression.

Kasambala of Human Rights Watch called the summit a positive development, noting that it is the first such meeting since the Zimbabwe crisis began seven years ago.

She said African governments should recognize that the millions of Zimbabwean refugees streaming into neighboring countries pose a threat to regional stability.

"This is a key threat to the region," she noted. "Therefore the southern African leaders should be the ones taking the lead in discussing the situation in Zimbabwe and we are glad that this is taking place and we hope that strong measures will be taken."

She said the African leaders should send a committee to Zimbabwe to investigate the violence and should impose sanctions if it is not ended.