The seven-page order, dated October 1, 1973 and found last week in the regional archive office in the eastern city of Magdeburg, shows that the Ministry for State Security, known as the Stasi, had told guards that they must "stop or liquidate" would-be dissidents.

"Do not hesitate to use your firearm, not even when the border is breached in the company of women and children, which is a tactic the traitors have often used," it said.

The director of the government office that manages the thousands of Stasi files still in existence said the document offered iron-clad evidence that the top echelon of the regime expected that anyone trying to escape to the West should be killed.

"The document is so important because the political leaders of the time continue to deny there was an order to shoot," Marianne Birthler told the Frankfurter Allgemeine Sonntagszeitung.

The orders were issued to a special Stasi unit which was posted alongside regular East German border guards in the Magdeburg region. Its job was to stop escape attempts by guards, who sometimes tried to flee with their families. It is believed that more than 2,800 East German soldiers crossed the border into the West. The unit was disbanded in 1985, four years before the Berlin Wall fell.

Several border guards were tried in the years after the East German government collapsed in 1990 but most received only suspended sentences.

Anniversary

Monday is the 46th anniversary of the start of construction of the Berlin Wall, which cleaved the city in half and symbolized the Cold War until it was toppled amid joyous scenes on November 9, 1989. Some 133 people were killed trying to cross it into West Berlin.

Estimates vary, but it is thought that more than 1,000 people lost their lives on the eastern side of the highly fortified border that ran along the entire frontier between the two Germanys.

"On the eve of the anniversary of the construction of the wall, it is a lesson to all of those who want to let the barbarity of the communist regime be consigned to the annals of history," Ronald Pofalla, general secretary of Chancellor Angela Merkel's Christian Democratic Party, told Berlin's BZ newspaper.

The total length of the Berlin Wall was 155 kilometers (about 97 miles), of which 43 kilometers ran roughly north-south, cutting the city in two, while another 112 kilometers isolated the enclave of West Berlin from the surrounding East German state.