The presidents of Italy and Germany paid a joint visit on Sunday to the site of a World War II massacre of up to 500 Tuscan villagers by the Nazi Waffen-SS.

The SS troops, who were hunting Italian resistance fighters in the final phase of the war, committed the atrocity in August 1944 in the village of Sant'Anna di Stazzema.

German President Joachim Gauck, the largely ceremonial head of state, and Italian President Giorgio Napolitano on Sunday visited the hill village in northern Tuscany.

"The victims have a right to be remembered and commemorated," said Gauck. "Here in Sant'Anna, human dignity was trampled and human rights massively violated."

In the massacre, the Nazis rounded up men, women and children and machine-gunned them before setting the corpses on fire and torching the entire village.

After the war, the massacre was long ignored and the files kept locked away in Italy until 1994. An Italian court later imposed life prison terms against several former SS troops.

However the men never went to jail. German prosecutors ran their own investigation but shelved it last year, citing a lack of solid evidence against any of the individuals.

A survivors' group condemned the decision as a scandal.