A group of leftwing politicians in Germany have been criticised for refusing to observe a minute's silence on Saturday to commemorate the 136-plus people who died trying to breach the Berlin Wall.

A far-left newspaper added to the controversy by printing a front page saying "thank you" to the wall for "28 years of keeping the peace in Europe" and "28 years of plentiful crèche and kindergarten places".

The timing of both stunts was provocative: Saturday marked 50 years since the East German government built what it euphemistically described as "an anti-fascist protection measure". To mark the date, a minute's silence was held across Germany at noon, with Angela Merkel attending an event on the former death strip in east Berlin.

But at a political conference in Rostock, in the former East Germany, three delegates from Die Linke party refused to join in when 100 colleagues stood up to observe the silence.

One was Marianne Linke, a regional politician from Die Linke, which has links to the old East German ruling socialist party. According to the tabloid Bild am Sonntag she tried to justify her actions by saying: "The border closure in 1961 would not have happened without fascist Germany." The implication being that the wall was either a rational reaction against a West that had not dealt with its Nazi past, or a result of the way the allies divided up Germany after the second world war.

Even the then US president, John F Kennedy, believed a wall was better than another war, she is alleged to have added.

Linke's comments were sharply criticised by Steffen Bockhahn, head of Die Linke in Mecklenburg Pomerania, where Rostock is located. "I am furious. It's disrespectful to the victims to stay seated. The building of the wall is nothing to be justified."

Die Linke have repeatedly caused controversy since forming in 2007. Gesine Lötzsch, national chair of Die Linke, caused a storm on Friday by describing the construction of the wall as a logical consequence of the war.

On Saturday the far-left weekly newspaper Junge Welt (Young World) marked the wall's anniversary with a front cover featuring a picture of armed East Berlin soldiers defending the German-German border at the Brandenburg Gate.

"Thank you" ran the headline, and underneath were 13 reasons to be grateful for the wall: "For 28 years without sending German soldiers to war … for 28 years without unemployment and unemployment benefit … for 28 years of no doctors' fees and no two-tier health system … for 28 years of education for all."

The story even paid tribute to 28 years of Club Cola, East Germany's answer to the Coca-Cola of the imperialist west, and of FKK, a nudist movement popular in East Germany.

Meanwhile, secret files obtained by Der Spiegel magazine apparently show that West Germany's post-war chancellor Konrad Adenauer wanted to "swap" West Berlin for a more convenient and fruitful bit of East Germany.

The western part of the divided capital was difficult to defend as it was an island in the middle of the German Democratic Republic (GDR). Adenauer is believed to have proposed a secret deal with the Soviet Union to the US foreign minister Dean Rusk just a few days before construction of the wall began on 13 August 1961.

According to Der Spiegel, the chancellor described the proposed deal as an "advantageous exchange" for West Germany. In exchange for relinquishing West Berlin Adenauer wanted the state of Thuringia, as well as parts of Saxony and the northern state of Mecklenburg-Vorpommern.

These were areas that had been occupied by British and US soldiers at the end of the war and then handed over to the Soviet Union in order to gain control of part of the capital. Adenauer apparently planned to reverse this deal.

The chancellor, who governed from 1949 to 1963, believed West Germany would gain prosperous new industrial areas in the deal. After initially taking Adenauer's idea seriously, Kennedy eventually "recoiled" from the proposal, Der Spiegel reported, and West Berlin remained marooned in the GDR until reunification on 3 October 1990.