This was a US special forces reconnaissance operation by the Office of Strategic Services in German-occupied Yugoslavia (August/22 September 1944).
The objective of the Office of Strategic Services in the Yugoslav theatre was to undertake as many offensive missions as possible into the Dalmatian coastal islands, where there were concentrations of German forces, and also to undertake reconnaissance and intelligence activities.
Troops of Company C destined for Yugoslav operations started arriving at Bari in south-eastern Italy, the OSS rear-echelon base, during January 1944. As more units came from the USA they transferred first to the vicinity of Manfredonia for additional training and next to Torre a Mare, a larger facility. Troops then were sent to the Dalmatian coastal island of Vis, where the first men arrived on 20 January. At this base for Yugoslav missions they became part of the Allied garrison, which included British commandos, the Raider Support Regiment and other British units, as well as partisans. Also available was naval and air support. The total of Allied troops on the island was several thousands.
Between January and June 1944, reconnaissance patrols of the Office of Strategic Services reached 10 Yugoslav islands and the mainland, several visits being made to each island each month. Officers and men in each party varied up to eight and were maintained on the island up to two weeks, and their objectives included liaison with the partisans of Marshal Josip Broz Tito, ground reconnaissance, and daily reports by radio to an advanced headquarters on the island of Vis. Reports were sent to British brigade ground forces, the Royal Navy, Royal Air Force, the partisans and Allied headquarters in Italy.
The reconnaissance parties took with them full equipment, weapons and rations, and the partisan forces provided transportation in small fishing boats and schooners, though at times British and US naval vessels aided the effort. Trips took two nights and were made hazardous by storms and the presence of German vessels. The accomplishment of their mission meant that the US troops had to live with the partisans, and on land the primary hazards were German patrols, extensive stormy weather and the delayed arrival of relief parties. However, no casualties resulted from the transportation missions.
On night of 2 September 1944 Lieutenant J. W. McConnell and Staff Sergeant B. Spiroff as interpreter left Italy and parachuted into the area of Yugoslavia to the east of Zara at the start of 'Adairville'. Two weeks later, on night of 16 September, Lieutenant M. C. Ward and six men made the jump into the same area, but the rest of the personnel, in two other aircraft, were prevented from jumping because of a change in the weather and returned to Italy.
When it became apparent that the partisans opposed activity in the area the full implementation of the operation was cancelled. The partisans assisted the party to the coast, whence it had returned to Torre a Mare via Vis by 6 October.