BEIJING — U.N. Secretary-General Ban Ki Moon joined the United States on Monday in ratcheting up pressure on North Korea by recommending Security Council action for a torpedo attack that killed 46 South Korean sailors.
Ban, formerly South Korea's foreign minister, called the evidence "overwhelming and deeply troubling" that Pyongyang was responsible for the March 26 sinking of the Cheonan in the Yellow Sea.
He urged the 15-nation council, as the U.N.'s powerful body, to respond to one of South Korea's worst military disasters since the 1950-53 Korean War.
The Obama administration announced Monday that it would bolster South Korea's defenses and initiate joint military exercises with Seoul.
"We have always tolerated North Korea's brutality, time and again. We did so because we have always had a genuine longing for peace on the Korean peninsula," South Korean President Lee Myung Bak said in a solemn speech at the War Memorial.
"But now things are different. North Korea will pay a price corresponding to its provocative acts," he said, calling it a "turning point" on the tense Korean peninsula, still technically in a state of war because the fighting ended in a truce, not a peace treaty.
In twin announcements, Secretary of State Hillary Rodham Clinton and the White House said U.S. forces in South Korea had been directed to "coordinate closely with their Korean counterparts to ensure readiness and to deter future aggression."
The officials were seeking to calibrate the response to North Korea cautiously in large part because of concern about how North Korea might react. The country's defense commission, which rarely issues public statements, has threatened direct attacks on South Korea if it retaliates for the sinking of the warship, though the North has denied responsibility
Still, moves by both the South and the United States make clear that they are including a significant military component to their response.
"The discipline of the armed forces will be re-established, military reform efforts will be expedited and combat capabilities will be reinforced drastically," Lee said Monday. He said the U.S.-Korean military alliance — there are almost 29,000 U.S. troops deployed in South Korea — would be strengthened.
The types of steps announced Monday have been tried before over the past two decades. While some have inflicted temporary pain, they have not deterred North Korea from conducting two nuclear tests since 2006, a battery of missile tests and the sale of nuclear and missile technology to the Middle East.
Lee's main moves against North Korea so far have involved trade. On Monday, he said the South would block all imports and exports from North Korea and cut off some investments; South Korean waters were closed to North Korean ships as well.
Lee's trade embargo will cost North Korea almost $500 million — about one-tenth of its total estimated exports and $326 million in imports.
The trade ban excluded the industrial enclave at Kaesong, where South Koreans run factories in the North, in part because it is home to more than 1,000 South Koreans. The factories account for most of the $1.7 billion in annual trade on the peninsula.
Speaking to reporters in Beijing, Clinton described the situation as "highly precarious." She said she was having "intensive consultations" with China about the issue, but it appeared that China did not want to take sides. Speaking to reporters, Foreign Ministry spokesman Ma Zhaoxu said that Beijing's position was "very clear" on the sinking and that both sides should "exercise restraint and remain cool-headed."