South Korea sought to portray its stunning rescue Friday of a cargo ship captured by Somali pirates as proof that it's ready and willing to take on aggressors from the Arabian Sea to North Korea.

An exultant President Lee Myung-bak appeared across national television networks Friday praising the Navy commandos who rescued all 21 crew members of the South Korean-owned freighter while killing eight pirates and detaining three.

"Our military carried out the operation perfectly under difficult circumstances," Mr. Lee said, adding: “We will not tolerate any behavior that threatens the lives and safety of our people in the future."

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Analysts say Lee's address was a thinly veiled warning to Pyongyang that South Korean forces are prepared to fight.

After being criticized for a weak response to North Korea’s bombardment of Yeonpyeong Island in the Yellow Sea, Lee has vowed to retaliate to future attacks. In recent months, the South has participated with the US in war games at sea and built up forces near its borders with the North. Today's attack on the pirates buttressed an increasing emphasis on South Korean defense in an atmosphere of rising tensions between the Koreas.

“Somali pirates clearly are not as dangerous as the Korean People’s Army,” says Andrew Salmon, a Korean War historian and Seoul-based journalist. ”Many South Koreans would like to see a muscular response, but the risks are far greater against the KPA.”

Still, he adds, “this is a very robust response by the South Koreans against a third-rate enemy" – and "sends a useful message to the North Koreans.”

During a crowded briefing at the Defense Ministry, South Korea’s command here described a five-hour battle in which heavily armed troops boarded the Samho Jewelry while a Lynx helicopter supported the attack and a destroyer waited nearby. The US command in Bahrain also had a destroyer on its way to the area, according to the South Korean report.

The chemical tanker was on its way from the United Arab Emirates to Sri Lanka when pirates captured it Jan. 15. The ship was 800 miles from the Somali coast when rescued.

The operation “demonstrated our government's strong will to never negotiate with pirates," Lt. Gen. Lee Sung-ho said at today's briefing.

Although Korean forces have averted several hijackings in the waters off the coast of Somalia, they failed to act in the case of the Samho Dream. Pirates held the oil tanker for 217 days until the ship's owner, South Korea-based Samho Shipping, paid a record $9.5 million ransom.

Choi Jin-wook, at the Korea Institute for National Unification, puts today's episode in the context of South Korean plans for operations against North Korea.

“This is a message we are not going to compromise with evil," he says. "It is our determination to fight.”

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