Following the June 1914 assassination of Archduke Franz Ferdinand of Austria there was growing talk of war in Europe. Churchill began readying the navy for conflict. Although there was strong opposition within the Liberal Party to involvement in the conflict, the British Cabinet declared war when Germany invaded Belgium. Churchill was tasked with overseeing Britain's naval warfare effort. In two weeks, the navy transported 120,000 British troops across the English Channel to France. In August, he oversaw a naval blockade of German North Sea ports to prevent them from transporting food by sea; he also sent submarines to the Baltic Sea to assist the Russian Navy against German warships. Also in August, he sent the Marine Brigade to Ostend to force the Germans to reallocate some of their troops away from their main southward thrust.