The United States on Wednesday announced new sanctions against North Korea, targeted against its leadership, and warned of serious consequences if it again attacked the South.
U.S. Secretary of State Hillary Clinton said the sanctions would be aimed at the sale or procurement of arms and related goods as well as luxury items used to fund the regime's activities.
The U.S. will freeze assets as well as prevent some businesses and individuals from traveling abroad, and collaborate with banks to stop illegal financial transactions. The sanctions also will seek to stop the abuse of diplomatic privileges in order to carry out illegal activities, Clinton said.
Relations across the divided peninsula have turned increasingly hostile after South Korea accused the North of sinking one of its warships in March, killings 46 sailors.
Clinton said Washington was ready to return to international talks over North Korea's nuclear weapons program if Pyongyang sent a "positive signal," but that there had been none so far.
Speaking at a joint news conference in Seoul after holding unprecedented security talks with U.S. and South Korean defense and military officials, Clinton said the sanctions were part of measures designed to rein in the regime's nuclear activities by stamping out illegal moneymaking ventures used to fund the program.
"We are aiming very specifically, after much intensive research built on what was done before but not limited to that, to target the leadership, to target their assets," Clinton said.
She insisted the additional sanctions were not aimed at ordinary North Koreans, who make up one of the world's poorest societies and whose stumbling economy is already largely sealed off from the outside world because of nuclear and missile tests.
The officials warned of "serious consequences" if there were any future North Korean attacks against the South.
Earlier in the day, Clinton and Defense Secretary Robert Gates made an unusual joint visit to the heavily defended demilitarized zone (DMZ) that divides the two Koreas amid a warning the peninsula faced a dangerous new period.
Nearly 2 million troops flank a 2.5-mile-wide strip of land that has kept the two Koreas apart for nearly 60 years and is one of the last relics of the Cold War.
Clinton said the North could have what it wants — a peace treaty, normal relations with the United States and an end to sanctions — if it ended its belligerence and took irreversible steps to end attempts to build atomic weapons.
"But until they change direction, the United States stands firmly on behalf of the people and the government of the Republic of Korea," she said.
The retired general nominated by U.S. President Barack Obama to be his intelligence chief said on Tuesday that the sinking of the South Korean warship Cheonan may herald a "dangerous new period" of direct attacks by Pyongyang on the South.
The warning by James Clapper at his Senate confirmation hearing for director of national intelligence put a spotlight on growing concern within the U.S. intelligence community and the Pentagon about what they see as the North's increasingly unpredictable behavior.
Gates earlier announced that joint U.S. and South Korean naval and air exercises would begin next weekend that will include the aircraft carrier USS George Washington and F-22 Raptor aircraft.
The planned exercises have been criticized by North Korea which accused the two allies of using them to prepare for an attack.
China, North Korea's only major ally, has also voiced its unease at the drills in its region and state television on Tuesday showed the Chinese navy conducting its own exercises that included helicopters and a submarine.
On Wednesday, China expressed "deep concern" about the joint military drills.
"We urge relevant parties to remain calm and exercise restraint and not do anything to exacerbate regional tensions," Chinese Foreign Ministry spokesman Qin Gang said in a statement.
Gates called for a resumption of military-to-military ties with China, suspended earlier this year over planned U.S. arms sales to Taiwan.
The concerns coincide with worries about the health of iron ruler Kim Jong-il, who appears to be trying to engineer the succession for his youngest son as leader of one of the world's most isolated countries, which has been pressing ahead with efforts to develop a nuclear arsenal.
North Korea has repeatedly argued that it has no choice but to build a nuclear deterrent in the face of U.S. aggression. Analysts say Kim uses the constant threat of war as justification to focus on maintaining one of the world's largest standing armies while the economy falls into near ruin.
"In the 20 years since I last climbed that observation tower and looked out across the DMZ, it's stunning how little has changed up there and yet how much South Korea continues to grow and prosper," said Gates. "The North, by contrast, stagnates in isolation and deprivation."