On 10th October 1943 the King of Italy, who with his Government had fled from Rome to Brindisi, declared war on Germany. Sporadic resistance to the Nazis began in German-occupied Italy almost immediately. In the mountain valleys and towns, armed groups were formed from Italian soldiers on the run - who feared deportation as forced labor to Germany - and escaped Allied POW's. Some of the more active partisans were Communist bands. The Communist Garibaldi band was active in the frontier area in north-East Italy, namely Friuli Venezia Giulia, and cooperated with Tito's partisans on the Yugoslav frontier. The Garibaldi made no secret of the fact that they supported Tito's claim to absorb the Venezia Giulia Region into Yugoslavia after the war.

On the other hand the Osoppo Partisan Brigade operated under the orders of the 'Committee of Liberation' which was formed to coordinate the resistance to German occupation by disparate partisan groups of diverse political persuasions. The 'Committee of Liberation' was comprised of the political parties that had been in hiding since their suppression by Mussolini in 1922. Their first acts were to aid escaping Allied POWs and deserters from the Italian army. By the end of November 1944, after further Cossack and German attacks, the Garibaldi partisans had dispersed to the East of the Isonzo River and passed completely under Yugoslav control. A few Osoppo partisans lay low in the high mountain villages where Cossack and German patrols did not penetrate.

A number of the Garibaldi objected to being under the Yugoslavs and deserted to the Osoppo. Both the Garibaldi leaders and the IX Yugoslav Corps were furious and their relations with both the Osoppo partisans and the British S.O.E. units supporting them became openly hostile. By February 1945 the Garibaldi Commanders had launched a violent anti-British and anti-American campaign which threatened the lives of British and American Commanders and resulted in the stealing of arms and money from British troops. However, the avowed intention of the Garibaldi partisans and the Yugoslavs was to destroy the Osoppo partisan units.

First commemoration of Porzus massacre First Commemoration of Porzus Massacre (Relatives who Ascended the Mountain Stall on Foot)
Partisans belonging to the Osoppo Brigade Osovani Partisans
Malga porzus 2010 The Mountain Stall nr. Porzus Where the Garibaldi Partisans Massacred the Osovani Partisans

The most infamous expression of such intention took place in the village of Porzus on the Zuffine pre-alpine mountain range which marks today's border between Italy and Slovenia and overlooks the village of Ravosa from behind. On 7th February 1945, the Garibaldi tricked the Osoppo Partisans into a meeting in a mountain cow stall above the village of Porzus. They then disarmed and executed fourteen Osoppo partisans. In a post-war well-known and much publicized trial the Communist leader Mario Toffanin, known as 'Giacca', who had commanded the ambush was condemned to death, but as he escaped to Yugoslavia the sentence could not be carried out immediately. After the war, Toffanin benefitted from the general amnesty promulgated by Palmiro Togliatti, minister of justice and leader of the Italian Communist Party. Toffanin continued to live in Slovenija near the Italian border and received an Italian pension which he would collect personally in Italy. He died in Slovenia in 1999.