Collecchio by 1st Brazilian Division being forced to surrender after some days of fighting. On 29 April, Graziani surrendered and was present at Caserta when a representative of German General Heinrich von Vietinghoff-Scheel signed the unconditional instrument of surrender for all Axis forces in Italy, but since the Allies had never recognised the RSI Graziani's signature was not required at Caserta. The surrender was to take effect on 2 May; Graziani ordered the RSI forces under his command to lay down their arms on 1 May. Air Force The National Republican Air Force (Aeronautica Nazionale Repubblicana or ANR) was the air force of Italian Social Republic and also the air unit of National Republican Army in World War II. Its tactical organization was: 3 Fighter Groups, 1 Air Torpedo Bomber Group, 1 Bomber Group and other Transport and minor units. The ANR worked closely with German Air Force (Luftwaffe) in Northern Italy, even if the Germans unsuccessfully tried to disband the ANR forcing its pilots to enlist in the Luftwaffe. In 1944, after the withdrawal of all German fighter units in the attempt to stop the increased Allied offensive on the German mainland, ANR fighter groups were left alone and heavily outnumbered to face the massive Allied air offensive over Northern Italy. In the operation time of 1944 and 1945, the ANR managed to shoot down 262 Allied aircraft with the loss of 158 in action. Navy Little of the Regia Marina (Royal Italian Navy) joined the RSI. This was because the bulk of the Italian navy was ordered to steam to Malta at the time of the armistice, out of reach of the Germans and the RSI. The RSI's National Republican Navy (Marina Nazionale Repubblicana or MNR) only reached a twentieth the size of the co-belligerent Italian fleet. The RSI Navy largely consisted of nine motor torpedo boats (two large and seven small), dozens of MTSM small motor torpedo boats and MTM explosive motorboats. The National Republican Navy also operated fifteen CB-class midget submarines (ten in the Adriatic and five in the Black Sea) and one larger submarine, CM1. Troops of the Decima Flottiglia MAS (elite Italian frogman corps) fought primarily as a land unit of the RSI. Some of the naval personnel at the BETASOM submarine base in Bordeaux remained loyal to Mussolini. Paramilitaries The fall of the Fascist regime in Italy and the disbandment of the MVSN