Published: May 26, 2010 12:31 PM EDT
Updated: May 26, 2010 9:31 AM EDT

SEOUL, South Korea (AP) - U.S. Secretary of State Hillary Rodham

Clinton said Wednesday the world must respond to the sinking of a

South Korean warship that has been blamed on North Korea.

"This was an unacceptable provocation by North Korea, and the

international community has a responsibility and a duty to

respond," Clinton told reporters after talks with South Korean

leaders.

The ship sinking "requires a strong but measured response,"

she said at a joint news conference with South Korean Foreign

Minister Yu Myung-hwan, though she did not elaborate.

Clinton said the United States would be consulting with South

Korea and members of the U.N. Security Council on what the

appropriate action would be, but she declined to offer a timeline.

"We're very confident in the South Korean leadership, and their

decision about how and when to move forward is one that we respect

and will support," she said.

Tensions on the Korean peninsula have risen sharply since a team

of international investigators last week concluded that a torpedo

from a North Korean submarine tore apart the corvette Cheonan on

March 26. It killed 46 South Korean sailors and was one of the

South's worst military disasters since the 1950-53 Korean War.

Clinton spent just a few hours in Seoul discussing possible

international responses with South Korean leaders. North Korea

denies it was to blame and has threatened any attempt to punish it

could lead to war.

Clinton arrived in the South Korean capital Wednesday after

intense discussions on the deteriorating Korean situation with

Chinese officials in Beijing.

"I believe that the Chinese understand the seriousness of this

issue and are willing to listen to the concerns expressed by both

South Korea and the United States," she said. "We expect to be

working with China as we move forward in fashioning a response."

China, the North's biggest ally, says it is still weighing the

evidence over the sinking.

Beijing regards the sinking as "extremely complicated" and has

no firsthand information about the cause, Vice Foreign Minister

Zhang Zhijun told reporters in the Chinese capital.

"China is carefully and prudently studying and examining the

information from all sides," he said.

South Korea's Yu, asked about the possibility of China or Russia

blocking action by the U.N. Security Council, said they "will take

time, I'm sure, but they will not be able to deny the facts."

Clinton called the investigation into the sinking "very

thorough, highly professional" and "very convincing." She said

both the United States and South Korea had offered China

"additional information and briefings about the underlying facts

of that event."

"We hope that China will take us up on our offer to really

understand the details of what happened and the objectivity of the

investigation that led to the conclusions," she said.

Earlier Wednesday, Clinton met South Korean President Lee

Myung-bak and discussed cooperation on the response to the ship

sinking.

Lee thanked Clinton for Washington's backing, while the top U.S.

diplomat replied that she came to South Korea to show her "clear

and unmistakable" support for Lee and his government, according to

Lee's office.

As Clinton visited Seoul, the two Koreas traded new threats amid

rapidly deteriorating relations.

The North's military said it would block cross-border traffic

heading to a joint industrial zone in North Korea if the South does

not stop psychological warfare operations. It also vowed to blow up

any loudspeakers South Korea sets up to broadcast propaganda

northward.

South Korea, meanwhile, accused Pyongyang of taking "menacing"

measures and vowed to "deal with these North Korean threats

unwaveringly and sternly," Unification Ministry spokesman Chun

Hae-sung said.