Overnight, North Korea fired artillery shells at Yeonpyeong, an inhabited South Korean island, prompting a response from South Korea and the scrambling of fighter jets. At least four soldiers were wounded in the attack, and according to the BBC two marines died.

It’s unclear why North Korea would suddenly shell the island. Pyongyang claimed that the South fired first. South Korea acknowledged that they were engaging in military exercises on Yeonpyeong, but were firing away from North Korea, in the opposite direction. The North Koreans claimed that they warned the South Koreans to stop the military drills.

In March, a torpedo sunk a South Korean warship, killing 46 sailors. But North Korea denied responsibility for that incident. In this case, the artillery shells clearly came from the North. In November 2009, the two countries traded volleys around their maritime border.

Yeonpyeong, which is two miles from a disputed naval border and twelve miles from the North Korean coast, has seen gunfire in the past, including an incident in 2002 that killed 13 Northern sailors and 5 Southern sailors.

The White House has denounced the attack. “The United States strongly condemns this attack and calls on North Korea to halt its belligerent action and to fully abide by the terms of the Armistice Agreement,” said Press Secretary Robert Gibbs in a statement.

There may be an emergency session of the UN Security Council today or tomorrow about the incident.

North Korean leader Kim Jong-il, currently believed to be ill, has turned over the reins to his son, Kim Jong-un, and this action could be related to ensuring the succession.

South Korean leader Lee Myung-bak called the attack a “clear armed provocation” and warned of retaliation.