Enlarge Pool photo by Kim Min-Hee South Korean President Lee Myung Bak speaks to his nation on Monday iin Seoul. South Korean and American military forces began war games exercises Sunday, as tensions between the two Koreas remain high following an artillery exchange on the disputed island of Yeonpyeong on Nov. 24. NORTH KOREA ACTION NORTH KOREA ACTION SEOUL  South Korea 's president told his nation today that he feels he failed to protect them from a deadly North Korean artillery barrage last week. As he spoke, U.S. and South Korean warships participated in military exercises in the Yellow Sea "I feel deeply responsible for failing to protect my people's lives and property," South Korean President Lee Myung Bak said. He also vowed that North Korea would face consequences for future aggression, but did not give specifics. China offered to broker talks to cool tensions. China's top nuclear envoy, Wu Dawei, called for an emergency meeting among regional powers. South Korea said it would review the offer but chastised China for doing nothing to rein in its ally. Meanwhile, South Korea's military said Monday that new artillery drills planned for the front-line island targeted in last week's deadly North Korean bombardment were postponed, hours after authorities on the island announced the exercises. Similar live-fire maneuvers by South Korean troops one week earlier triggered the North's bombardment that decimated parts of Yeonpyeong Island, killed four people and drew return fire in a clash that set the region on edge. The new drills originally planned for Tuesday could have had even higher stakes: South Korean and American warships are currently engaged in separate military exercises in nearby waters. Officials at the Joint Chiefs of Staff told reporters Monday that the latest drills were postponed, saying that the marine unit on the island mistakenly had announced the drills without getting approval from higher military authorities. They spoke on condition of anonymity, citing agency rules. The cancelation has nothing to do with North Korea and the drills will take place at a later date, one of the officials said. Some Seoul residents said they are torn by how to deal with North Korea. "Part of me wants our president to be stronger, and I welcome his promise that we will defend ourselves in the future," businesswoman Kim Hye Sung, 33, said. "On the other hand, I am afraid if he attacks North Korea it will be World War Three." Hotel worker Park Chan Seong, 27, echoed fears of war. "I am worried North Korea could be angered by the (joint U.S., South Korea military) exercises" and attack again. China has yet to blame North Korea for the attack Tuesday on Yeonpyeong, a few miles from the North Korean border. Two South Korean marines and two civilians were killed. China protested the arrival Sunday of the USS George Washington to the Yellow Sea off the coast of South Korea. The aircraft carrier arrived from Tokyo with other U.S. vessels. South Korean soldiers laid down an aluminum road to prepare for an amphibious landing drill today. The exercises had been planned before the latest incident and are well south of the disputed maritime border between North and South Korea. WAR GAMES: U.S., S. Korea launch exercises as tensions rise Minutes after Lee spoke, North Korea called the joint war drills "yet another grave military provocation." North Korea threatened to launch counterattacks on South Korea and U.S. forces if they engage in provocation again, according to commentary carried by the official Korean Central News Agency. Chinese analysts doubted that China could do much to contain the North. "China's influence on North Korea is limited," said Jin Canrong, an international relations expert at Renmin University in Beijing. "The North is pretty good at playing off different countries, getting aid from various parties, but staying quite independent." China is a main supplier of food and oil to the North. Seoul said it will reconsider sending more food aid to the North after having shipped thousands of tons of rice and instant noodles last month. Up to a million or more people have starved to death under the repressive communist regime, according to the United Nations. Arizona Sen. John McCain, the top Republican on the Senate Armed Services Committee, told CNN that China should get control of its neighbor. "The key to this, obviously, is China," McCain said. "And, unfortunately, China is not behaving as a responsible world power. It cannot be in China's long-term interest to see a renewed conflict on the Korean Peninsula." Contributing: Sunny Yang in Beijing; the Associated Press Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. 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