BEIJING // Tensions between North and South Korea heightened yesterday with each country vowing to react forcefully to provocation from the other.
Also, Seoul's defence minister quit over what some saw as a weak response to an attack from Pyongyang earlier this week.
Kim Tae-Young resigned after the deaths on Tuesday of two civilians and two military personnel, killed when North Korea shelled Yeonpyeong island.
Seoul yesterday said it would bolster its military presence on five Yellow Sea islands close to North Korea, partly by increasing the number of troops.
As criticism grew in South Korea over the country's handling of the crisis, Seoul's senior public affairs secretary, Hong Sang-Pyo, said the country had laid down tougher rules of engagement.
These would scrap the "rather passive" previous guidelines and "change the paradigm itself of responding to North Korea's provocation".
South Korean forces yesterday countered suggestions they had responded slowly to North Korean shelling, with the Marine Colonel Joo Jong-Hwa insisting they "did very well" by returning fire in 13 minutes.
"The soldiers did not desert and in the midst of a rain of fire, they pinpointed the target and started firing, which has never occurred in the past," he said.
Meanwhile, Pyongyang yesterday warned it would strike again if there were further "military provocations". North Korea has insisted it acted in response to firing into its territory by the South Korean military.
Pyongyang would launch "without hesitation the second and third retaliatory blow", according to comments from North Korea's official KCNA news agency reported by China's Xinhua news agency.
North Korea described the US, which has about 28,000 military personnel in South Korea, as shielding the "South Korean puppet forces".
Media in South Korea yesterday reported the North Korean leader Kim Jong-Il and his youngest son and heir apparent Kim Jong-Un had visited the Yellow Sea artillery base that fired at Yeonpyeong only hours before the bombardment. This adds credence to suggestions that the attack was a way of cementing the son's position with the military before a transfer of power.
More than 1,000 Yeonpyeong residents have reportedly fled the island, which was home to 1,600 civilians and 1,000 military personnel. Some of those still there, such as Park Sun-Bi, said they wanted to leave. Dozens of houses were destroyed and neighbourhoods reduced to blackened rubble.
"I'm just going to pack some things I need. Why stay here? There's nobody here now. They're all gone," she told media in her unlit and unheated home.
"I wonder if I will ever return."
The atmosphere on the Korean peninsula is likely to remain edgy, as South Korea and the US are preparing for four days of joint naval exercises beginning Sunday, with the aircraft carrier USS George Washington scheduled to take part.
Such drills have previously been condemned by China, although yesterday its response was muted. A spokesperson said only that concerns had been expressed about the exercises. Beijing has, however, resisted pressure to condemn Pyongyang. State media said it was impossible to tell who fired first, and yesterday its foreign minister cancelled a visit to South Korea.
Tensions between North and South Korea have been high since the sinking in March of the South Korean naval vessel Cheonan. This incident, which caused 46 deaths, was widely blamed on Pyongyang although it has denied responsibility.
Analysts have suggested North Korea's actions this week, and its recent showing to an American scientist of advanced uranium enrichment facilities, are designed to increase its bargaining position in stalled six-party talks over its nuclear programme.
The US envoy on North Korea, Stephen Bosworth, ruled out the resumption of the talks after the uranium enrichment disclosures, but Russia and China have since called for them to resume.
Although some analysts have said Beijing would have been unlikely to have known ahead of time of Pyongyang's actions on Tuesday, one expert yesterday took the view that China might have implicitly sanctioned them.
Chan Chepo, an assistant professor of political science at Lingnan University in Hong Kong, said recent tensions between China and its neighbours might have made Beijing more tolerant of North Korean actions.
"Allowing North Korea to do this bombing is a sign. I think it's a kind of warning to the USA and to South Korea, maybe as well as Japan," he said.
* With additional reporting by Reuters and Agence France-Presse