The newly formed Yugoslav 4th Army, whose elements were present at the pivotal Battle of Knin, spent most of spring advancing north along the Dinaric Alps from their staging grounds on the banks of the Neretva with the intent of reaching the Isonzo and taking Trieste without help from Western Allies, thereby justifying a claim to the de jure Italian port.

On the Italian front, Western Allied forces advanced towards Trieste after breaching the Gothic Line in early March 1945.

Under Lieutenant General Sir Bernard Freyberg, the New Zealand 2nd Division, having captured Faenza on 14 December 1944, reorganized on the south banks of the Senio River on 8 April 1945.

[1][9] Civil authorities in Trieste, formally part of the Italian Social Republic although under de facto German control through the Operational Zone of the Adriatic Littoral, consisted of prefect Bruno Coceani and podestà (mayor) Cesare Pagnini.

Admiral Raffaele de Courten, Chief of Staff of the Italian Co-belligerent Navy, had answered positively, and a landing by forces of the Regia Marina, with the support of the Decima Flottiglia MAS and of other RSI troops, had been planned, with or without Allied intervention; the plan however failed due to British opposition.

It was decided that the 1,800 men of the Civic Guard (Trieste's municipal police, raised by Coceani in 1944) would have also passed under the command of the CLN.

[10][11][12][13][14] On 28 April Bruno Sambo, head of the local PFR, handed over the arms of the fascist party to Coceani's public health committee, and agreed to replace the party insignia with tricolor ribbons; that same evening some Italian police units came out on the streets with the tricolor ribbons, but were quickly disarmed by the Germans.

[4]:282–283 The city was jointly occupied by the New Zealanders and Partisans until June 1945, when it came under rule of a UN-mandated military provisional government as a provision of the Treaty of Peace with Italy.