YEONGJONG ISLAND, South Korea | On their island base in a tense Yellow Sea, black-clad commando squads armed with automatic weapons surge up ladders onto the deck of a training ship, fast-rope down building exteriors and detonate explosives.
The Special Sea Attack Team (SSAT), an elite South Korean Coast Guard unit tasked with countering maritime terrorism, is preparing to respond with tougher policies to North Korean shipping in response to North Korea's missile launches and its second nuclear test in May. North Korea fired four short-range missiles into waters off the east coast Thursday, Yonhap news agency reported.
"We have not got word from above yet," said Inspector Joung Ku-so, who was suited in body armor and bristling with weapons. "But we are practicing boarding drills for PSI," he said, referring to the U.S.-led Proliferation Security Initiative that aims to block ships from carrying weapons materials to the North.
North Korea is expected to test its long-range Taepodong-2 intercontinental ballistic missile (ICBM) on Saturday, to coincide with Independence Day celebrations in the United States.
The PSI comprises more than 90 nations that have agreed to monitor and possibly inspect North Korean ships suspected of carrying illicit cargoes. Currently, a U.S. Navy destroyer is shadowing the North Korean freighter Kang Nam 1 in the South China Sea. The freighter's movements are also being monitored electronically at the South Korean Coast Guard station at Incheon.
Boarding a Coast Guard hovercraft off Incheon - South Korea's second-largest port and the location of its main international airport - for the 30-minute ride to the SSAT base, it is clear how dangerous these waters are. Coast Guard cutters mount 20 mm rotary chain guns; in the event of war, they would support naval operations.
The sea is gray and choppy, and fog often cuts visibility to zero. Mud flats and islands dot the estuary off Incheon, which lies just 20 miles south of the maritime border. Craft from South Korea, North Korea and China compete over the rich crab fishing.
Incheon was the scene of Gen. Douglas MacArthur's September 1950 seaborne landing that turned the tide of the 1950-1953 Korean War. Moreover, it was on an island off Incheon in 1969 where South Korea trained criminals in a "Dirty Dozen"-style unit in an attempt to assassinate North Korean leader Kim Il-sung. That incident was depicted in the hit 2003 South Korean film "Silmido." Mr. Kim died of natural causes in 1994.
In June 1999 and June 2002, North Korea initiated naval clashes in these waters, killing six South Korean sailors. At the time, governments in Seoul were following an engagement "sunshine policy" toward Pyongyang and withheld policies and comments that could antagonize the North.
Now, under the leadership of conservative President Lee Myung-bak, policies are tougher.
"The guidelines for rules of engagement have changed," said Coast Guard spokesman Yun Byeong-du. "In the past, vessels had to get permission from the Blue House [presidential residence] to retaliate. Now it is up to captains." The Coast Guard is just the front line in the toughest South Korean defense posture in more than a decade.
Last week, the defense ministry told the nation's parliament that South Korea was boosting its pre-emptive strike capabilities to counter the North's missile and nuclear threat. According to Yonhap, South Korea's military has moved air and artillery assets to the Yellow Sea border region as insurance against possible North Korean gunboat or missile attacks.
While the 1.19 million men of the North Korean People's Army vastly outnumber South Korea's 655,000 soldiers, analysts think the northern force is a paper tiger. Its soldiers are poorly nourished and lack both modern equipment and adequate fuel for training.
North Korea is estimated to have more than 300 artillery pieces dug in along the Demilitarized Zone that could hit Seoul, but military specialists say this gun line could be outflanked by airborne or marine landings - assets the North Korean military, lacking a maneuver element and operating without air superiority, would have difficulty countering.
And while Pyongyang's 120,000-strong commando force appears formidable, a defector from one of those units, Kim Shin-jo - captured during a 1968 raid - has said that special forces alone are not a viable threat absent an uprising among South Korea's populace. A pro-North Korea rising by affluent, sophisticated and well-informed southerners seems a remote possibility.
For this reason, many specialists think Pyongyang is building a nuclear missile-based deterrent. This is tacit recognition that its conventional military is no match for the South Korea-U.S. alliance.
"North Korea is the weakest state in the region," said Dan Pinkston, who heads the International Crisis Group's Seoul office. "They don't have the technological or economic base to compete conventionally, so they have to rely on asymmetric capabilities." In a possible indication of the North's lack of conventional strength, no clashes took place in June in the Yellow Sea despite numerous predictions that North Korea would launch naval provocations there following its recent missile and nuclear tests.
Yonhap, citing an unnamed military official, reported that all four missiles fired Thursday flew about 60 miles and identified them as KN-01 missiles with a range of up to 100 miles.
President Obama told the Associated Press in an interview Thursday that he was trying to "keep a door open" for North Korea to return to international nuclear disarmament talks, but the country must abandon its nuclear weapons programs before it can join the world community.
He expressed optimism that he could get international agreement for even tougher action if North Korea does not heed warnings to pull back.
"In international diplomacy, people tend to want to go in stages," Mr. Obama said. "There potentially is room for more later."
White House press secretary Robert Gibbs told reporters later that the Obama administration was not surprised by the missile test, saying that it was probably not the last challenge the North Koreans would pose the international community.
"The North Koreans said they were going to launch these missiles. I don't think it's surprising that they've launched these missiles," Mr. Gibbs said. "I take the North Koreans at their word that they're going to continue their provocative actions."
Christina Bellantoni in Washington contributed to this report.