SEOUL North Korea appears to be preparing to test-launch its longest range ballistic missile, media reports said on Tuesday, just days after Pyongyang warned that the Korean peninsula was on the brink of war.
Analysts say the possibility that North Korea would start an all-out war with the South is low because Pyongyang knows its underfunded military is no match for the U.S.-backed modern military of its Southern neighbor.
But the following scenarios could unfold:
A NAVAL SKIRMISH
The North has threatened military action over a disputed sea border off the west coast and it previously triggered clashes in 1999 and 2002 that killed or wounded dozens of sailors on both sides. The 1999 battle was orchestrated by the North's military with its leader Kim Jong-il's close involvement and caught the South by surprise, according to intelligence sources.
The North may be hesitant to spark another battle after its navy was badly outgunned by a superior South Korean force in the last firefight in 2002. Since then, the North's Soviet-era navy has become more obsolete while the South's has increased its firepower and technology.
What has changed is the North's deployment of more short-range missiles. The North could raise tension by firing missiles into waters claimed by the South or at one of its ships.
A shootout along the Demilitarized Zone border could easily ignite a broader gunfight involving many of the more than 1 million troops who are deployed on both sides of the buffer zone that has divided the peninsula since the 1950-53 Korean War ended in a ceasefire and not a peace treaty.
But a land battle is unlikely because of the chance it could trigger a bigger conflict. A more likely scenario is for the North to conduct massive military training maneuvers or send aircraft just close enough to the border so that the South has no choice but to respond.
A MISSILE LAUNCH
The North could raise regional tension by testing its ballistic missiles, which have the range to hit all of South Korea and most of Japan. It could go ahead and fire its long-range Taepodong-2 missile. South Korea's Yonhap news agency quoted an unnamed South Korean government source as saying the North had a newly constructed launch pad on its west coast.
The last time North Korea launched a Taepodong-2 in 2006, the missile fizzled less than a minute into flight and destructed.
A successful test would boost support at home for North Korea's leaders and raise alarm in Japan and the United States because it increases the chances that the two countries could be targets of North Korean missiles.
SECOND NUCLEAR TEST
The North could set off a nuclear device again. The first test in October 2006 was considered by South Korea and the United States as only a partial success, which indicted flaws in the North's weapon design or materials. The North needs a second test to see if it has fixed those problems, experts say.
But a second test carries major risks to the isolated state because it is certain to strain ties with its biggest benefactor China and lead to a new round of international trade sanctions.
North Korea might feel it can win more over the long term from new U.S. President Barack Obama if it ups the stakes. In order to increase its leverage, the North could begin to restore operations at its Soviet-era Yongbyon nuclear plant and reverse disablement steps called for in an international deal that were designed, in total, to put the facility out of business for at least a year.
The North's most likely priority would be restoring its facility that separates plutonium from spent nuclear fuel. Experts say the North could have it up and running again in a few months. There are discharged, irradiated fuel rods cooling at Yongbyon that the North could use to produce what experts say would be enough plutonium for one more nuclear weapon.
U.S. military commanders in South Korea have said U.S. and South Korean forces would be able to quickly defeat the North, even though the North would still be able to quickly fire off thousands of artillery shells as well as launch missiles that could hit South Korea and Japan. Analysts say an all-out war would bring the end of Kim Jong-il's government, cause enormous destruction on the peninsula, and perhaps Japan. It could also plunge the regional economy, and even the global economy, into a tailspin.
South Korea has 670,000 soldiers backed by 28,000 U.S. troops. North Korea has a military of 1.2 million personnel.
(Additional reporting by Junghyun Kim; Editing by Jon Herskovitz and Dean Yates)