South Korea found the burnt bodies on Wednesday of two islanders killed in a North Korean artillery attack, marking the first civilian deaths in the incident and dramatically escalating the tensions in the region’s latest crisis.

The South Korean Coast Guard pulled the bodies of two men, believed in their 60s, from a destroyed construction site on the tiny island of Yeonpyeong near the disputed maritime border with North Korea.

The North’s artillery barrages targeting the island on Tuesday also killed at least two South Korean marines and wounded 18 other people in what U.N. Secretary—General Ban Ki-moon called one of the “gravest incidents” since the end of the Korean War.

President Barack Obama underlined Washington’s pledge to “stand shoulder to shoulder” and protect its ally Seoul and called upon China to restrain its ally Pyongyang. Seoul and Washington reaffirmed plans to stage joint military exercises later this week in the Yellow Sea, just 70 miles (110 kilometers) south of the island.

South Korean troops on high alert

South Korea’s troops, which returned fire during Tuesday’s hour-long skirmish, remained on high alert as exhausted evacuees from the island streamed into the port city of Incheon, greeting tearful family members and telling harrowing tales of destruction.

“I heard the sound of artillery, and I felt that something was flying over my head,” said Lim Jung-eun, a 36 year-old housewife who escaped Yeonpyeong island with her three children, one of whom, a nine-month-old baby girl, she carried on her back. “Then the mountain caught on fire.”

Civilian deaths are rare in clashes between the Koreas. Most of the skirmishes between the Koreas involve military casualties.

Sinking of Cheonan

In March, North Korea was blamed for launching a torpedo that sank the South Korean warship Cheonan while on routine patrol, killing 46 sailors. South Korea at the time called it the worst military attack on the country since the war. Pyongyang denied responsibility.

The North’s most notorious act of terrorism was the 1987 bombing of a South Korean airliner that claimed 115 lives. And in 1996, 60,000 South Korean soldiers hunted down a group of North Korean spies who slipped ashore from a submarine and killed three civilians and a South Korean army private while roaming the countryside for weeks.

After the attack on Yeonpyeong, more than 500 people arrived on Wednesday on the first ships from the island, the coast guard said.They were greeted with hugs and tears by family members at the port; some, mostly the elderly, were taken to a line of ambulances waiting nearby.

Stories of destroyed homes and panic

There were stories of destroyed homes and panic.

“Right after I saw the news, I called my daughter,” said Chung Doo—sun, a 55-year-old man from nearby Gimpo city. “She was crying and told me the windows of her home were all shattered.”

His son-in-law, a marine on the island, was not hurt and will stay on the island. Mr. Chung said he only slept one hour because of worries about his daughter and grandchildren, who were also safe.

“I’ll never allow my daughter and my grandchildren to go back to Yeonpyeong island,” Mr. Chung said. “North Korea is so unpredictable.”

In the crowd at the port was a 68 year-old South Korean man, who was waiting for his 46-year-old son and his daughter-in-law.

"Provocation near island"

“I’m always worried about my son, because North Korea has always committed provocation near the island,” said the man, who would only identify himself by his family name Kim.

“North Korea has not changed at all,” Mr. Kim said. He said he still holds bitter memories of the Korean War. “They are so cruel.”

The scene at the port contrasted with the calm in Seoul, South Korea’s capital of more than 10 million people, where citizens went about their business Wednesday with shops, offices and financial markets open as usual, but with the previous day’s skirmish weighing on people’s minds.

“We are concerned that a war might break out,” said Oh Duk-man, who was walking in downtown Seoul.

Pedestrian's reaction

In Young—joo, another pedestrian, called for a strong response. “Our government has to react very strongly against North Korea after they invaded us in such a daring way,” she said.

South Korea said on Wednesday it would strengthen military forces in the disputed western waters near Yeonpyeong and to halt aid to the communist North, while the North warned of more military strikes if the South encroaches on the maritime border by “even 0.001 millimeter.”

The skirmish began on Tuesday when North Korea warned the South to halt military drills near their sea border, according to South Korean officials. When Seoul refused and began firing artillery into disputed waters, but away from the North Korean shore, the North retaliated by shelling Yeonpyeong, which houses South Korean military installations and a small civilian population.

Seoul's response

Seoul responded by unleashing its own barrage from K—9 155mm self-propelled howitzers and scrambling fighter jets. Two South Korean marines were killed in the shelling that also injured 15 troops and three civilians. Officials in Seoul said there could be considerable North Korean casualties.

At a military hospital in Seongnam, just outside of Seoul, relatives wailed in grief as they filed out of a memorial on Wednesday for the two marines killed in the artillery barrage.

“Bring him back!” Kim O—bok, 50, cried out about her 22-year-old son, Seo Jeong-woo, as she fell forward and relatives supported her.

Shin Hyun-don, head of South Korean Joint Chiefs of Staff’s Operation Planning Department, said South Korea’s military “cannot help suppressing anger towards North Korea’s inhumane atrocities indiscriminately firing artillery at defenseless civilians residents.”

“We also severely warn North Korea that we will punish them strongly if there are any further provocations,” he said.

Relations plunge to new lows

North Korea’s apparent progress in its nuclear weapons programme and its preparations for handing power to a new generation have plunged relations on the heavily militarized peninsula to new lows in recent weeks.

North Korea does not recognize the western maritime border drawn unilaterally by the U.N. at the close of the conflict, and the Koreas have fought three bloody skirmishes there in recent years. But this clash follows months in which tensions have steadily risen to their worst levels since the late 1980s, when a confessed agent for North Korea bombed a South Korean jetliner, killing all 115 people aboard.

The government in Pyongyang has sought to consolidate power at home ahead of a leadership transition and hopes to gain leverage abroad before re-entering international talks aimed at ending its nuclear weapons programmes.

In March, North Korea was blamed for launching a torpedo that sank the South Korean warship Cheonan while on routine patrol, killing 46 sailors. South Korea blamed Pyongyang and called it the worst military attack on the country since the war. Pyongyang denied responsibility.

Six weeks ago, North Korean leader Kim Jong Il anointed his youngest son, Kim Jong Un, heir apparent. This week, Pyongyang claimed it has a new uranium enrichment facility, raising concerns about its pursuit of atomic weapons.

Yeonpyeong lies a mere seven miles (11 kilometers) from, and within sight of, the North Korean mainland. Famous for its crabbing industry, it is home to about 1,700 civilians as well as South Korean troops. There are about 30 other small islands nearby.

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