Railway officials in Mozambique are blaming an extraordinary error of judgement by one of their drivers for causing the worst rail disaster in the country's history.

The driver apparently used four large stones to stop passenger carriages from rolling downhill after his train lost power, but the makeshift brake gave way sending nearly 200 people to their deaths.

An investigation is still under way, but at first glance, the crash was caused by a human error

Transport Minister Tomas Salomao

The crash happened at Muamba on the main rail line between the Mozambique and South Africa, about 60 kilometres (40 miles) north of the capital, Maputo.

President Joachim Chissano has declared three days of national mourning for the people who died in the crash.

Hundreds more people were injured in the accident, and President Chissano urged people to donate blood to help treat them.

Buried alive

Antonio Libombo of the Mozambican Railway Company said the train had experienced mechanical difficulties as it tried to climb a hill on a mountainous stretch of the line.

The driver therefore disconnected the passenger section of the train, which was already half way up the hill, from the cargo section, which he took back to the nearest station.

The driver wedged the four stones under the wheels of the passenger section to keep it from sliding backwards before he drove off, Mr Libombo said.

However, the official said, the stones gave way and the passenger train careered down the tracks into the freight train, whose cargo was mainly cement.

Reports said dozens of passengers were buried alive by choking cement dust.

"An investigation is still under way," Transport Minister Tomas Salomao said. "But at first glance, the crash was caused by a human error."

Harrowing scenes

Staff from the transport ministry, fire department and ports and railway ministry worked overnight to clear the track and retrieve the last bodies.

Officials said two passenger carriages were completely destroyed.

Doctors complained of a shortage of blood and drugs

Emergency workers told harrowing tales of passengers dying in their arms because they could not get them out of the wreckage quickly enough.

"Everything is destroyed, there are bodies that have been cut in half and we don't know how to match them up, there are severed limbs," one police officer said.

Ambulances and private cars ferried the injured to hospital in Maputo.

At the main hospital in the capital, scores of people lay on thin foam mattresses on the floor.

President Chissano - who cut short a visit to his home village on hearing of the accident - visited victims in the hospital wards as well as going to the mortuary.

Civil war

The train had come from the western town of Ressano Garcia, on the border with South Africa, and was bound for Maputo with mostly women traders on board.

Rail transport is very important in Mozambique, a country which went through a devastating 17-year civil war.

The conflict ended nearly a decade ago, but not before it obliterated much of Mozambique's transport networks and infrastructure.

Intensive use of land mines in the conflict has also made many areas and routes hazardous.

But Mozambique has experienced significant economic development since the civil war ended. It is a transit route for many products from South Africa to other landlocked countries in the interior like Malawi, making transport a critical link.