Uryū decided to send his transports to unload their troops in the port as the Russians would be unlikely to initiate hostilities in neutral territory amidst the Western ships. Just in case, he ordered three of his cruisers to escort the troop ships into harbor with the two first cruisers to later rejoin the rest of the Fourth Division blockading the port. The following morning Uryū announced that a state of war existed between the Russian and Japanese Empires and the Russian commander decided to attempt to break through the blockade even though he was heavily outnumbered. His ships sortied later that morning and Naniwa was among the ships that badly damaged Varyag and forced the Russian ships to return to Chemulpo where Varyag was scuttled and Korietz was blown up later that afternoon. After the battle, the Fourth Division was tasked to protect the Korean coast between Chemulpo and Asan and to cover the movement of IJA reinforcements through the former port. On 10 March the division ineffectually bombarded what the Japanese believed to be a naval mine control station on an island near Port Arthur. The following month, raids by the Russian cruisers based in Vladivostok under the command of Rear Admiral Karl Jessen caused Tōgō to task Kamimura with the defense of the Sea of Japan and the Tsushima Strait, for which task he was reinforced with the Fourth Division. At the end of April Kamimura took his ships to lay minefields off Vladivostok. Uryū attempted to intercept the Russian cruiser squadron after it sank three transports on 15 June, but could not locate them in stormy weather. During another raid by the Russians at the end of the month, Kamimura's ships spotted the enemy ships, but lost contact with them after nightfall. Battle off Ulsan The Russian Pacific Squadron was supposed to break through the Japanese blockade of Port Arthur and rendezvous with the Vladivostok cruiser squadron near the Strait of Tsushima on 10 August, but Admiral Wilgelm Vitgeft, commander of the Pacific Squadron, failed to coordinate with Jessen and the latter's ships were unprepared to immediately sortie when Jessen was surprised to receive a telegram from Port Arthur stating that Vitgeft's ships were at sea on the afternoon of 11 August. Jessen's ships were only able to depart late the following morning and were out of radio range before they could be told that the