Russia had no more troops to throw against Plevna, so the Russians besieged it, and subsequently asked the Romanians to cross the Danube and help them. On 9 August, Suleiman Pasha made an attempt to help Osman Pasha with 30,000 troops, but he was stopped by Bulgarians at the Battle of Shipka Pass. After three days of fighting, the volunteers were relieved by a Russian force led by General Radezky, and the Turkish forces withdrew. Soon afterwards, Romanian forces crossed the Danube and joined the siege. On 16 August, at Gorni-Studen, the armies around Plevna were placed under the command of the Romanian Prince Carol I, aided by the Russian general Pavel Dmitrievich Zotov and the Romanian general Alexandru Cernat.