Alarmed that the Allies were working their way up the Solomons chain, the Japanese bombed the new American base in the Russells and began strengthening their own airfields at Munda and at nearby Vila on Kolombangara Island. In turn, the Americans attempted to subdue Munda field with naval gunfire with limited success. During the course of one of these overnight bombardment sorties, on the night of 6–7 March 1943, an American force consisting of three light cruisers and three destroyers under the command of Rear Admiral A. Stanton Merrill encountered two Japanese destroyers as they were returning to the Kula Gulf from delivering food and supplies to the garrison at Vila. In the ensuing action, known as the Battle of Blackett Strait, both Japanese destroyers were sunk.