Hunyadi proceeded to form a relief army, and assembled a fleet of 200 ships on the Danube. The flotilla assembled by Hunyadi destroyed the Ottoman fleet on 14 July. This triumph prevented the Ottomans from completing the blockade, enabling Hunyadi and his troops to enter the fortress. The Ottomans started a general assault on 21 July. With the assistance of crusaders who were continuously arriving to the fortress, Hunyadi repulsed the fierce attacks by the Ottomans and broke into their camp on 22 July. Although wounded during the fights, Sultan Mehmed II, decided to resist, but a riot in his camp forced him to lift the siege and retreat from Belgrade during the night.