South Korea vs North Korea

South Korea  North Korea said on Friday it would strike again at the South if a live-firing drill planned by Seoul on a disputed island went ahead, with an even stronger response than last month's shelling that killed four people. North Korean official news agency KCNA said the "intensity and scope" of its retaliation will be worse if the Seoul goes through with its announced one-day live-fire drills sometime between Saturday and Tuesday on Yeonpyeong Island. The North said the planned drills were an attempt "to save the face of the South Korean military, which met a disgraceful fiasco" during last month's clash. The North responded to similar South Korean drills on Nov. 23 by raining artillery shells on the tiny fishing community near the Koreas' disputed sea border. The South has said the drills are part of "routine, justified" exercises. Representatives of the U.N. Command that oversees the armistice that ended the Korean War will observe the drills. Later on Friday, Russia's foreign ministry summoned the South Korean and U.S. ambassadors to express "extreme concern" over the drill. Russian Deputy Foreign Minister Alexei Borodavkin met with the envoys and "insistently urged the Republic of Korea and the United States to refrain from conducting the planned firing," the ministry said in a statement. North Korea's warning came after Seoul promised a more robust response to any further attacks on its territory. The shelling of the island was the first time since the Korean war that the North had attacked South Korean territory. China, the North's main backer, has said that Pyongyang had promised restraint and the threat of a new attack by the North came as China told visiting U.S. Deputy Secretary of State James Steinberg that the two big powers should cooperate more in defusing tension on the Korean peninsula. It also came as U.S. diplomatic troubleshooter Bill Richardson visited Pyongyang in an effort to "reduce the tension on the Korean peninsula". China's top diplomat, Dai Bingguo, urged closer coordination over the Korean peninsula during talks with Steinberg, the second most senior official in the U.S. State Department, the state-run Xinhua news agency reported on Friday. Steinberg was in Beijing for three days up to Friday to press China to do more to bring to heel its ally, North Korea, which last month sparked alarm by shelling the island and disclosing advances in uranium enrichment which could give it a new path to make nuclear weapons. China has avoided publicly condemning its long-time ally over the deadly shelling and nuclear moves, and instead pleaded with other powers to embrace fresh talks with North Korea.