Osman could move out to relieve it. The Ottoman army organized the survivors of Lovech into 3 battalions for the Plevna defenses. Osman also received a reinforcement of 13 battalions, bringing his total strength to 30,000 men-the highest it would reach during the siege. In August, Romanian troops led by General Alexandru Cernat crossed the Danube and entered the battle with 43,414 men. On 11 September the Russians and Romanians mounted a large-scale assault on Plevna. The Ottoman forces were dug in and equipped with German Krupp-manufactured steel breech-loading artillery and American-manufactured Winchester repeaters and Peabody-Martini rifles. For three hours they pushed back the waves of advancing Russians with superior firepower. Czar Alexander II and his brother Grand Duke Nicolas watched from a pavilion built on a hillside out of the line of fire. Skobelev took two southern redoubts. The Romanian 4th division led by General George Manu took the Grivitsa redoubt after four bloody assaults, personally assisted by Prince Carol. The next day, the Turks retook the southern redoubts, but could not dislodge the Romanians, who repelled three counterattacks. From the beginning of September, Russian losses had amounted to roughly 20,000, while the Ottomans lost 5,000–6,000. Fourth battle Growing Russian and Romanian casualties put a halt to frontal assaults. General Eduard Ivanovich Totleben arrived to oversee the conduct of the siege as the army chief of staff. Totleben had proven command experience in siege warfare, having gained renown for his defense of Sevastopol (1854–1855) during the Crimean War. He decided on a complete encirclement of the city and its defenders. Osman requested permission from his superiors to abandon Plevna and retreat, but the Ottoman high command would not allow him to do so. By 24 October the Russians and Romanians had closed the ring. Supplies began to run low in the city, and Osman finally made an attempt to break the Russian siege north-west, in the direction of Opanets. On 9 December the Ottoman forces silently emerged in the dead of night, threw bridges over and crossed the Vit River, attacked on a two-mile front, and broke through the first line of Russian trenches. Here they fought hand to hand and bayonet to bayonet, with, at first, little advantage to either side; however, outnumbering the Ottoman forces almost 5 to 1, the Russians and Romanians eventually drove them back across the Vit, wounding Osman in the process (he was