SEOUL (AFP/Reuters) South Korea Wednesday pulled the bodies of two civilians from wreckage left by North Koreas bombardment of a border island, fuelling calls for revenge on what one newspaper called a mad dog regime. The United States and South Korea announced a joint naval show of force including a US aircraft carrier to deter the North, which killed a total of four people in its first shelling attack on civilians since the 1950-53 war. Coastguards searching shattered buildings on Yeonpyeong island found the bodies of the two elderly building workers a day after two marines were confirmed dead and 18 other people injured. Pressure rose on Beijing to rein in its wayward ally Pyongyang, which again asserted that Seoul had provoked the clash. South Korea, after decrying an inhumane atrocity against defenceless civilians, said it was suspending promised flood aid to North Korea. It has already called off talks on reuniting families split since the war. The bombardment of Yeonpyeong, which lies near the disputed inter-Korean Yellow Sea border, sent panicked civilians fleeing and fuelled anxiety about North Koreas intentions - days after a new nuclear programme came to light. Japans Prime Minister Naoto Kan called on China to use its significant influence over North Korea to reduce tensions. A White House statement said President Barack Obama telephoned his counterpart Lee Myung-Bak to declare that the United States stands shoulder to shoulder with South Korea, which is home to 28,500 US troops. The four-day joint naval exercise will start Sunday in the Yellow Sea, and involve a strike group headed by the carrier USS George Washington, US Forces Korea said. It said the drill was planned well before the unprovoked artillery attack but it demonstrated the US commitment to regional stability through deterrence. The nuclear-powered USS George Washington, which carries 75 warplanes and has a crew of over 6,000, left a naval base south of Tokyo and would join exercises with South Korea from Sunday to the following Wednesday, US officials in Seoul said. Outraged Seoul newspapers urged the government to hit back. South Korea said it would deploy more artillery on Yeonpyeong after officials announced that the North had fired up to 170 shells, of which 80 hit the island - burning down 19 homes and other buildings and setting forests and fields ablaze. Local officials who visited the island released graphic photos of scorched and ruined buildings, with debris littering the streets. At least 700 people have fled Yeonpyeong, which is home to more than 1,500 civilians and a permanent military base. The attack targeted our land and attacked civilians, President Lee was quoted by his spokesman as saying as he ordered military reinforcements for five frontline islands. The number of victims may be small but the meaning is far bigger. Defence Minister Kim Tae-Young pledged to revise the code of engagement to ensure troops respond more strongly in any future clash. On Tuesday the South fired 80 rounds back at the Norths coastal artillery batteries. China - North Koreas main ally and economic prop - has expressed concern but not publicly criticised the North. Its media have given generally sympathetic coverage to Pyongyangs version of events. The North criticised the South for scrapping the planned talks on family reunions. It repeated claims that Seoul provoked the artillery attack by firing into the Norths territory.