U.S. Secretary of State Hillary Rodham Clinton plead to the world that they should respond to the “unacceptable provocation” represented by the sinking of a South Korean warship blamed on Pyongyang.

“This was an unacceptable provocation by North Korea, and the international community has a responsibility and a duty to respond,” Clinton told reporters in Seoul, the final leg of a three-nation Asian tour.

Tensions went high between South and North Korea after international investigators said a week ago that a torpedo fired by a North Korean submarine tore apart and sank the South Korean warship Cheonan on March 26, killing 46 sailors. North Korea called the investigation a fabrication accusing US President Barack Obama behind it.

“As a matter of fact, the Obama administration is straining the situation in a bid to beef up its forces in the region and tighten its military domination,” the official Korean Central News Agency said in a commentary.

South Korea started measures against North Korea by slashing trade, resuming propaganda warfare, and barring cargo ships. North Korea warned them that they will blow up any propaganda speakers installed at the borders. They have also started barring South Korean ships and airliners from passing through its territory.