A recently discovered remnant of the Berlin Wall is being given protected status, city authorities have said.

The announcement by the city government's culture ministry came on the day when the wall has been open for as long as it divided Berlin: 28 years, two months and 26 days.

An amateur historian said last month that he had found the 80-metre stretch of wall and reported it to authorities because of concerns about its condition.

The old brick wall in the city's Pankow district was incorporated into communist East Germany's original fortifications when the border with West Berlin was sealed in 1961.

It was expanded and topped with a wire barrier as part of efforts to prevent East Germans fleeing to the West.

The remnant illustrates how existing structures initially were incorporated into the wall to enable the quick sealing of the border, the city government said.

The border fortifications were expanded over the years, and the barrier was far more sophisticated by the time it was opened in 1989.

Most of the wall was demolished starting in 1990, and only a few preserved sections remain.

The newly discovered remnant of the original wall was transferred to the West Berlin district of Reinickendorf in 1988 in one of several minor modifications to the border during the Cold War.

That appears to be one reason why it escaped researchers' attention until recently.