North Korea Bombards South

(Nov. 23) -- North Korea fired more than 100 artillery shells onto a South Korean border island today, killing two southern marines and wounding 18 others in a brazen attack that prompted the South to return fire and put its military on its highest alert. South Korea's president said he would unleash "enormous retaliation" should the North strike again.

President Barack Obama was awoken around 4 a.m. with news of the clash, and is phoning South Korea's president, the BBC reported.

U.N. Secretary-General Ban Ki-moon called it "one of the gravest incidents since the end of the Korean War," a spokesman told The Associated Press. The United Nations Security Council plans to hold an emergency meeting today or Wednesday to discuss the attack, a French diplomat told Reuters.

Fires burned out of control on Yeonpyeong Island, one of South Korea's closest territories to the communist north, which houses a South Korean military base alongside the homes of about 1,700 civilians. At least three civilians and 15 South Korean troops were among those wounded, a defense official told The New York Times.

"I ran outside my house when my windows shattered from the blasts," resident Lee Jong-sik told the JoongAng Daily newspaper. She said blasts rang out across the island every five minutes. It was the first time in 50 years the island has suffered any attacks, she said.