Johannesburg/Harare  - Zimbabwean Prime Minister Morgan Tsvangirai left hospital on Saturday one day after a road accident that left him injured and claimed the life of his wife Susan, as his supporters began questioning the cause of the crash.

Tsvangirai left hospital in Harare wearing a head bandage, and was met by supporters. Reports said that he then flew to neighbouring Botswana for rest and to come to terms with the loss of his wife.

In a statement released in South Africa Saturday, Tsvangirai's party, the Movement for Democratic Change (MDC) described the crash as a "perfect organised hit".

In Zimbabwe, leading MDC members stopped short of such a direct accusation, but said they were making their own investigations, and accused the government of failing to provide the protection of a police escort for Tsvangirai.

Tsvangirai survived with minor injuries after his vehicle was hit by an oncoming truck and overturned, but his wife of 31 years, Susan, was killed.

In a statement from Johannesburg, MDC spokesman in South Africa Sibanengi Dube said: "The truth of the matter is that this not a genuine accident.

"This is a perfect organised hit which was designed to eliminate the president of the MDC. We sincerely believe that the powerful but notorious Zanu-PF (party of President Robert Mugabe) clique is determined to do anything to scamper efforts by the inclusive government to get Zimbabwe back on track."

Dube did not offer any evidence to back up the MDC's accusation. While Zimbabwe's under-maintained road network is notoriously dangerous, Mugabe's regime also has a long history of assassination plots and some former opposition figures have died in car crashes.

Initial investigations into the crash suggest that the truck which collided with Tsvangirais' sports utility vehicle (SUV) belonged to a US aid organisation, according to media reports in South Africa.

The driver of the truck has been arrested, according to the reports, while Mugabe has attempted to contact the US ambassador.

According to the same media reports, Tsvangirai - the prime minister for just over three weeks in an uneasy power-sharing coalition government with longtime-foe Mugabe
- may be transferred to a South African specialist clinic.

Mugabe visited Tsvangirai in hospital on Friday night. The crash happened on the road near Beatrice, about 60 kilometres south of Harare.

The MDC in Zimbabwe, while not going as far as Dube in accusing the Mugabe government, nevertheless criticised authorities there for failing to provide a police escort.

MDC Secretary-General Tendai Biti - who was in tears as he addressed reporters as was MDC Vice-President Thokozani Khupe - said the MDC was investigating how the accident had taken place.

"The accident was a disaster for us," he said. "If there had been a police escort, maybe what happened yesterday could have not have happened.

"A police escort would have warned oncoming vehicles of a VIP arriving. I think authorities must understand the omission. That omission could have avoided the loss of life.

"We hope that this omission will be rectified, that the prime minister must be given the protection that ought to be accorded to a prime minister, namely travelling with a police escort."

In a statement on Saturday, South African President Kgalema Motlanthe sent Tsvangirai' the best wishes of his nation.

"The thoughts and prayers of the people of South Africa and the Southern African Development Community region are with you while wishing you a speedy recovery to enable you to resume your national responsibilities as prime minister," Motlanthe said.

Zimbabwe is in the grip of its most severe crisis in recent times, with hyperinflation, mass poverty and hunger, and a cholera outbreak which has killed around 4,000 people.

Tsvangirai defeated Mugabe in a presidential poll last year, but the result was not recognised - despite international outcry - after the president declared turnout was insufficient to declare a mandate.

The MDC leader then withdrew from a subsequent run-off election, after a campaign of violence and harassment against his supporters. (dpa)