YEONPYEONG ISLAND // South Korea has vowed to boost military forces on frontline islands with North Korea, which warned of more possible strikes after its artillery attack sent tensions soaring.
Two days after the bombardment, workers were clearing the rubble on the Yellow Sea island of Yeonpyeong, where 80 shells rained down on Tuesday, killing four people in the first such attack since the 1950-53 Korean War.
South Korea's military, after media criticism of an allegedly weak response, plans to change its "rather passive" rules of engagement, said senior public affairs secretary Hong Sang-Pyo.
It will also "sharply increase military forces, including ground troops, on the five islands in the Yellow Sea and allocate more of its budget toward dealing with North Korea's asymmetrical threats", he said.
The explosions that shattered the calm of the remote islet killed two marines and two civilians, wounded 18 other people, left 22 buildings in charred ruins and sent hundreds of terrified residents fleeing to the mainland.
Newspapers have called for revenge against the "mad dog" regime, protesters have burnt North Korea's flag, and some politicians have berated President Lee Myung-Bak for not responding forcefully enough when the South returned fire.
North Korea on Thursday blamed the South and the United States for provoking its artillery bombardment and warned it was ready to strike again in case of further provocation.
The reclusive communist state has also rejected a proposal by the US-led United Nations Command, which supervises the armistice, to hold military talks on the attack, Yonhap reported, citing a South Korean defence official.
Pyongyang charged in a statement that "the US can never evade responsibility for the recent exchange of fire", blaming it for overseeing the drawing up of the post-war maritime border which the North considers illegal.
"If the war-mongering South Korean puppets fail to return to their senses and commit another reckless military provocation, our army will carry out second and third rounds of powerful physical retaliatory strikes without hesitation."
The US and South Korean navies plan to hold a four-day naval exercise in the Yellow Sea from Sunday that will involve a strike group headed by aircraft carrier the USS George Washington.
US President Barack Obama has pledged to stand "shoulder to shoulder" with ally South Korea, where 28,500 American troops are stationed. They face off across a Cold War era frontier against the regime run by "Dear Leader" Kim Jong-Il.
The world has often been baffled by the regime, which has staged two nuclear tests, fired missiles over Japan and this month showed off to a US academic a modern new nuclear facility.
Many observers believe Tuesday's attack was meant to highlight the military credentials of the leader-in-waiting -- Kim's little-known 27-year-old son Kim Jong-Un, who two months ago took powerful military and political posts.
The opaque nature of the regime, and its history of brinkmanship, has left world powers at a loss at how to deal with Pyongyang -- a problem vastly compounded by divisions within the international community.
While the US, European powers, South Korea and Japan have long pushed hard to sanction the regime, China and Russia have favoured a softer line with Pyongyang, a Cold War era ally and neighbour to both.
When an inter-governmental expert panel found that a North Korean submarine in March torpedoed and sank a South Korean corvette the Cheonan, killing 46 sailors, China refused to blame the Pyongyang regime.
Its foreign minister Yang Jiechi postponed a planned trip to South Korea due to start on Friday because of what Seoul called a scheduling problem.
Premier Wen Jiabao said in Moscow that "China is firmly committed to maintaining the peace and stability of the Korean peninsula and opposes any provocative military acts".
It was not clear whether Wen was referring to the North Korean shelling or to the planned US-South Korean military exercises. Beijing has bitterly opposed similar war games in the Yellow Sea in the past.
"In the wake of the Cheonan sinking, Beijing showed us that they are more than willing to put up with Pyongyang's worst behaviour," said North Korea expert Peter Beck, with the US think tank the Council on Foreign Relations.
"Given that this incident brings us closer to the brink of war than the Cheonan, Beijing might conclude that enough is enough and quietly put their foot down, but I am not holding my breath."