North Korea's barrage of missile tests and a recent underground nuclear blast have unnerved many South Koreans. Yet for all the scaremongering on the Korean peninsula, an all-out attack by either side is unlikely.
Six decades ago, communist North Korea caught South Korea and its American allies off guard with an invasion that sent more than 180,000 troops and 240 Soviet-made tanks storming across the frontier, setting off a war that devastated the Korean peninsula.
Such a surprise attack wouldn't be easy today: Tens of thousands of South Korean troops stand guard along the 154-mile (248-kilometer) border, the world's most fortified. Watchposts and barbed wire line roads heading south, and huge blocks of concrete are ready to be dropped to obstruct the advancement of communist tanks.
South Korea's 650,000 forces are bolstered by 28,500 American troops in the country. The U.S. also has F-16 jets and A-10 attack aircraft in South Korea, while its F-16s in Japan could reach North Korea in an hour.
"I'm sure that the North Koreans know very well that they cannot win," said Yang Moo-jin, a professor at Seoul's University of North Korean Studies.
He and other analysts say it's more likely North Korea's recent missile and nuclear tests are aimed at mustering domestic support for ailing leader Kim Jong Il as he reportedly prepares to name his youngest son as his successor.
"North Korea has many internal problems now: Kim's uncertain health problem, the power succession matter and the country's economic trouble," Yang said. "Given all these, the North is not in a situation to start a war."
Still, the string of North Korean provocations has sparked concern to the south. A June 20 poll showed that some 60 percent of those surveyed felt "very uneasy" or "uneasy" about the overall security situation on the Korean peninsula, twice as high as three months earlier. The telephone survey of 800 people by polling company Hankook Research had a sampling margin of error of plus or minus 3.5 percentage points.
But on the streets of Seoul, few are panicking. Many rushed to supermarkets to stock up on instant ramen noodles and other provisions after Pyongyang abandoned an international nonproliferation treaty in 1993 and then-North Korean leader Kim Il Sung died of heart attack in 1994.
Yet South Koreans appear largely inured to the most recent threats from the North. Financial markets have shrugged off the nuclear tensions, with the benchmark stock index rising 26 percent this year despite the global economic downturn.
The tension is most palpable in government and military circles.
Late last month, the South Korean military took the unusual step of publicizing plans to develop the capability to strike first if it suspects an attack is imminent.
Days later, North Korea launched its biggest display of missile firepower in three years: seven ballistic missiles fired on July 4 as Americans celebrated Independence Day.
"We'll expand our surveillance, precision-striking and interception capabilities ... to obstruct and eliminate North Korea's asymmetric threats in its territory as much as possible," army Lt. Gen. Kim Ki-soo said last month, referring to the North's nuclear and missile arsenals.
Under the South Korean plan, unmanned reconnaissance aircraft and a satellite monitor the North's missile and nuclear sites around the clock. Fighter jets would scramble to strike a missile base if the South detects signs of an imminent attack. The plan would require buying more sophisticated jets, precision bombs, Patriot anti-missile batteries and other advanced equipment.
For its part, North Korea is in no position to invade the South. Much of its military equipment is decrepit, and the country's weak economy and chronic food shortages raise the question of how long it would be able to wage a war.
At most, Pyongyang may instigate a skirmish along the western sea border, scene of deadly naval clashes in 1999 and 2002, analysts said.
"They can get their warships to simply violate the border or get them to maneuver provocatively near our navy ships," said Kim Tae-woo, an analyst at the Korea Institute for Defense Analyses in Seoul.
Still, the North has sufficient firepower to make the U.S. and South Korea think twice about a pre-emptive strike. North Korea has 1.2 million troops, the world's fourth-largest army, and 13,000 pieces of artillery, mostly deployed near the border.
Gen. Walter Sharp, commander of U.S. forces in South Korea, told Congress in March that the North has more than 80,000 commandos ready to infiltrate the South. It has the largest special operating force in the world, he said, with "tough, well-trained and profoundly loyal troops."
But U.S. and South Korean forces are prepared for "anything North Korea can throw at us," he said Tuesday.
With Seoul just 40 miles (65 kilometers) from the border, a North Korean attack could be swift and damaging.
"Seoul will be a sea of fire," said Kim Seong-man, a retired three-star South Korean navy admiral, echoing a phrase that stoked jitters in the South when used by a senior North Korean official in 1994.
In addition to its troops in Korea, the U.S. has another 50,000 in nearby Japan. Highly mobile and combat-ready, it would be a decisive factor should a shooting war break out.
Besides air bases in northern and southern Japan, the U.S. has U-2 spy planes in Osan south of Seoul.
"I don't think a total war will break out as the North knows the U.S. would enter the conflict if it happens," said 72-year-old Oh In-kyu, who recalled the frightening booms of North Korean artillery and the piles of corpses during the Korean War. "The North wouldn't start a war. It's just bluffing."
Associated Press writers Eric Talmadge in Tokyo and Foster Klug in Washington contributed to this report.