Zimbabwe's President Robert Mugabe has gone to meet his fellow heads of state in Tanzania in a defiant mood.
By Martin Plaut
BBC News Africa analyst
Mr Mugabe's defiance has won the day with his counterparts in the past
He may appear to be in a corner, with the world's fastest-shrinking economy, massive food shortages and pressure from the international community.
But Mr Mugabe has been in a corner before and knows how to respond.
An indication of his response came in the state-run Herald newspaper.
It accused the opposition Movement for Democratic Change (MDC) of using an underground organisation, the Democratic Resistance Committees, to unleash what were described as "orgies of violence to create mayhem and render Zimbabwe ungovernable".
A police spokesman, assistant commissioner Wayne Bvudzijena, accused the committees of being behind eight petrol bomb attacks in the past 12 days.
"These are clearly acts of terrorism," he said.
The opposition believes President Mugabe will present the Southern African Development Community (SADC) leaders with a dossier outlining these charges in detail.
He will then challenge them to side with him, as a leader of a liberation movement, or with "terrorists" backed by imperialist forces.
This is the language the president has used time and again, tying in alleged plots by Britain and the West in general to destabilise his government.
In the past this defiance has won the day. But it may not work much longer.
Reluctant as the rest of the region will be to take on Mr Mugabe, he is now a real threat to regional stability.
As Zambian President Levy Mwanawasa said last Friday, Zimbabwe is like the Titanic and if it sinks it could take its neighbours down with it.
Zimbabweans have little food and little prospect of getting more.
Mr Mbeki (L) has favoured "constructive diplomacy"
Only a third of the 1.8m tonnes of maize the country needs will be harvested this year.
An estimated 2m Zimbabweans are said to be so desperate they could flee across the country's borders if the economic situation worsens.
While Malawi has some surplus grain, the rest of the region is also short of food and could be overwhelmed.
South Africa is also increasingly worried about the impact of Zimbabwe's instability on its own position.
While President Thabo Mbeki insists he is engaged in "constructive diplomacy" with his northern neighbour and that Zimbabwe's problems must be solved by Zimbabweans, it is clear he is delivering a tougher message in private.
When the two men met in Ghana for the country's 50th anniversary celebrations this month Mr Mbeki told Mr Mugabe he was determined that the 2010 World Cup planned for South Africa would not be placed in jeopardy.
Some European nations have begun contemplating challenging South Africa's suitability as a venue if chaos in Zimbabwe deepens.
This is something that President Mbeki will not be willing to tolerate.
The talks in Tanzania are likely to be more frank and direct than anything President Mugabe has ever experienced from his fellow African heads of state.