South Korea has not openly put the blame on North Korea for the March 26 blast that broke the 1,200-ton Cheonan in half during a routine patrol near the tense border with North Korea.
But officials have said they are open to the possibility that a North Korean naval mine or torpedo may have hit the vessel. On Friday, an investigator said the sinking was likely caused by an external explosion, rather than by a blast of munitions stored in the ship or the vessel hitting an underwater rock.
North Korea on Saturday denied its involvement in the blast.
Fifty-eight of the ship's crew were rescued and 38 bodies have been found, most of them Thursday when the stern was raised from the water. Eight crew members are still unaccounted for.
“I promise to you. As the president, I will fully find the cause of the Cheonan's sinking to the last,” Lee said in a nationally televised speech. “I will resolutely and unwaveringly cope with the results” of the investigation.
Lee said he will make South Korea's military stronger to prevent similar incidents from happening but didn't mention North Korea.
His 10-minute speech was emotional as he wiped away tears with his handkerchief after calling the names of all of the dead and missing sailors.
“The country that you loved will not forget all of you forever,” Lee said.
The site of the sinking is near where the two Koreas fought three bloody sea battles since 1999. The Koreas are still technically at war, since the 1950-53 Korean War ended in a cease-fire, not a peace treaty.
North Korea on Saturday accused the South Korean government of spreading false rumors linking Pyongyang to the incident to shore up international sanctions against it and muster conservative votes to boost its prospect for June's mayoral and gubernatorial elections.
The United Nations Security Council slapped tough new sanctions on North Korea following its second nuclear test last year.
Lee's foreign minister has said that South Korea may ask the Security Council to take up the sinking if it learns North Korea was behind the blast.
“Though it's hypothetical, I think if it was confirmed to have been committed by North Korea, what we can consider doing first of all is referring this matter to the UN Security Council,” Foreign Minister Yu Myung-hwan told a KBS television program broadcast Sunday. “We can discuss (how to respond to North Korea) after referring it to the UN Security Council.” Yu, however, reiterated that an investigation was ongoing, and it was still too early to determine what caused the blast.
The government is making preparation for how to act depending on all possible outcomes of the investigation but it's “not appropriate” to disclose them in details, he said.
