During this period, the Russian Black Sea Fleet was operating against Ottoman coastal traffic between Constantinople (currently named Istanbul) and the Caucasus ports, while the Ottoman fleet sought to protect this supply line. The clash came on 30 November 1853 when a Russian fleet attacked an Ottoman force in the harbour at Sinop, and destroyed it at the Battle of Sinop. The battle outraged opinion in UK, which called for war. There was little additional naval action until March 1854 when on the declaration of war the British frigate Furious was fired on outside Odessa harbour. In response an Anglo-French fleet bombarded the port, causing much damage to the town. To show support for Turkey after the battle of Sinop, on the 22th of December 1853, the Anglo-French squadron entered the Black Sea and the steamship HMS Retribution approached the Port of Sevastopol, the commander of which received an ultimatum not to allow any ships in the Black Sea.