Koreans woke up today to the reality that life on their divided peninsula has been plunged back to the worst days of the Cold War, even as doubts were emerging about the sinking of a South Korean gunboat that sparked this latest crisis.
South Korea's President Lee Myung-bak promised yesterday that Pyongyang would “pay a corresponding price” for its attack on the frigate in March which killed 46 sailors.
Announcing the severing of all trade links with the impoverished North, the president told his people in a televised address they had forgotten “that the nation faces the most belligerent regime in the world”.
“We have always tolerated North Korea's brutality, time and again,” said Mr Lee.
“We did so because we have always had a genuine longing for peace on the Korean peninsula. But now things are different.”
The speech, and Mr Lee's demand for a North Korean apology, follows the publication of a report last week presenting “clear and definitive material evidence” that Pyongyang was behind the gunboat attack.
North Korea's government has branded the report a “fabrication” and called yesterday's sanctions an “intolerable, grave provocation” to the country
Meanwhile, UN Secretary-General Ban Ki-Moon said that he expected “measures appropriate to the gravity of the situation” to be taken by the Security Council when South Korea brings the subject to the body's attention.
And he told a news conference that the evidence of North Korea's responsibility was “overwhelming and deeply troubling”.
The US Secretary of State Hillary Clinton was working to persuade China, Pyongyang's sole ally, to line up with Seoul, Washington and their allies in a united front against the isolated Stalinist state in referring the sinking of the vessel to the Security Council.
But as tensions ratcheted up, some were already questioning the evidence produced by a team of international investigators that blamed Pyongyang for the 26 March incident. Former unification minister Chung Se-hyun yesterday told the South Korean media that lettering found on the North Korean torpedo that supposedly split the frigate in two was not North Korean at all.
Allegations have also surfaced that South Korean and US forces were conducting joint military exercises in the area of the incident, raising the possibility that the Cheonan was instead sunk by friendly fire from an American submarine.