Mr Allende's family has always accepted the official version.

But some of his supporters suspected he had been killed by soldiers.

Allende, who was 65, died in La Moneda presidential palace on 11 September 1973 as it was being bombed by air force jets and attacked by tanks.

The official version was that he shot himself - with a rifle given to him by his friend, the then Cuban leader Fidel Castro - as troops stormed the palace.

Mr Allende's family agreed to have his body exhumed from a cemetery in the capital, Santiago, so that an international team of experts, including specialists in ballistics, could determine the cause of death.

The official report handed in to the Chilean government concludes that Mr Allende was killed by two bullets shot from a rifle held between his legs.

British ballistics expert David Prayer took part in the investigation and said the result was clear.

"The gun, an AKA rifle, was on automatic," he said.

"There was one wound in his skull, caused by two bullets. There is no evidence that a third person was involved," said Mr Prayer.

Senator Isabel Allende, a daughter of the late president, said the family had received the news with great peace.

"The report conclusions are consistent with what we already believed. When faced with extreme circumstances, he made the decision of taking his own life, instead of being humiliated," Ms Allende said.

Salvador Allende, a member of the Socialist Party, became the first left-wing president of Chile when he was elected in September 1970.

He introduced a number of economic reforms, including the nationalisation of the mining industry, that angered the opposition and the US government at the time.

A series of strikes paralysed the country and left the capital isolated in the tense days that preceded the coup.

On 11 September 1973, President Allende was tipped off that part of the military would launch an attack to remove him from power.

He turned up at the Palacio de La Moneda carrying a rifle and ready to co-ordinate the resistance, witnesses said.

The coup led to 17 years of military rule under Gen Pinochet. More than 3,000 political opponents were killed or "disappeared" by the military.

Investigators are looking into more than 700 cases of alleged human rights abuses.

The legacy of Salvador Allende remains a divisive issue in Chile. For some, Mr Allende was a reckless Marxist, intent on turning Chile into another Cuba.

For the left, he was a democratic socialist and a victim of one of several US-sponsored military coups in Latin America in the 60s and 70s.