Tensions on the Korean peninsula: What you need to know

Tensions are near the boiling point on the Korean peninsula after North Korea shelled a South Korean island, killing two South Korean soldiers. What's behind this latest spike in hostilities between the longtime adversaries, and just how concerned should we be -- especially since we have 25,000 military personnel stationed in South Korea?  Here's what you need to know.

What happened, exactly?

Early Tuesday, North Korea fired artillery shells at the South Korean island of Yeonpyeong, which sits off the disputed maritime border between the two countries. The attack killed two South Korean marines and wounded 18 soldiers and civilians.  It prompted an exchange of fire between the two sides, involving around 175 artillery shells and lasting about an hour.

The North accused South Korea of having started the exchange by firing shells inside North Korean territory during a set of South Korean military exercises that the North called "war maneuvers."  The South denies that charge, saying that its soldiers were merely conducting military drills and that no shots fell in North Korean territory.

The North Korean attack was the first on a civilian area of South Korea since the Korean War.

[Photos: North Korea fires on island of Yeonpyeong]

Why did this happen now?

Tensions have been running high since March, when a South Korean naval vessel in the same area was sunk, killing 46 sailors. Seoul blamed a North Korean torpedo attack, though the North has denied involvement. Then earlier this month, the South Korean navy fired warning shots at a North Korean fishing boat after the craft strayed across the border. The North Korean boat retreated.

Some analysts have linked Tuesday's action by the North to the impoverished nation's need for food. The Obama administration has refused to remove sanctions against the North, imposed in response to its nuclear program. "They see that they can't pressure Washington, so they've taken South Korea hostage again," Choi Jin-wook, a senior researcher with the South Korean Institute for National Unification, told the New York Times.  "They're in a desperate situation, and they want food immediately, not next year."

Does this have anything to do with North Korea's leadership situation?

Kim Jong Il, the North's ailing and reclusive leader, is believed to be  gradually shifting power over to his son, Kim Jong Un, who in September was promoted to the rank of four-star general.

[Related: U.S. boy found in China, protesting for Korean peace]

Some analysts believe the transition has made North Korea eager to demonstrate its military power.  Kim Jong Il famously employed an aggressive "military first" approach to politics, and spoke of turning the North Korean army into a "pillar of the revolution."  The regime may now want to show the world that the same military-first policies will prevail under his successor. "The son's power base is derived from the military, and the power of [the] military is greater than ever," Cheong Seong-Chang, a fellow at the Seoul-based Sejong Institute, told Time magazine.

How has the world reacted?

The United States, Britain and Japan have condemned the North Korean attack, with America calling on the North to "halt its belligerent action." China said it was "concerned," while Russia has urged restraint and a peaceful solution to the crisis.

What's the U.S. role in all this?

The United States wants North Korea to resume the six-party talks on the country's nuclear program. The talks, which also include Russia, China, Japan in addition to America and the two Koreas, were launched in 2003, after North Korea opted out of the Nuclear Nonproliferation Treaty. The talks' aim is to arrive at a peaceful diplomatic agreement to contain the North's nuclear capacity -- but the talks have been in limbo since 2008, and earlier this week, an American scientist revealed that he had been shown a sophisticated North Korean nuclear enrichment facility, throwing the resumption of the talks into further doubt.

[More details: U.S., China disagree on more nuke talks with N. Korea]

Today's incident adds another obstacle, experts say.

The revelation of the uranium facility and Tuesday's attack on South Korea may both be expressions of the North's concern that the Obama administration and its allies are unlikely to offer concessions such as the easing of sanctions. "I think they realize they can't expect anything from Washington or Seoul for several months, so I think they made the provocation," Choi Jin-wook, senior researcher at the Korea Institute of National Unification, told CNN.

How scared should we be?

South Korea has placed its military on "crisis status," and Prime Minister Lee Myung-bak has reportedly ordered strikes on North Korea's missile base if the North makes any "indication of further provocation." It appears unlikely, though not impossible, that further military action will result. 

[Photos: N. Korean leader Kim Jong Il and more]

South Korea does not have an active nuclear weapons program. North Korea is believed already to have eight to 12 nuclear bombs. But nuclear issues aside, any military conflict between the countries could badly destabilize the region, especially if the North Korean government were to collapse -- an outcome that some South Koreans fear could lead to a Chinese takeover.

(Photo: Yonhap via AP)

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