国际英语新闻：S Korea continues search for 46 missing sailors

The image, taken by a marine unit who used a thermal observation device shortly after it heard the explosion that caused the sinking of the ship, only showed the bow of the ship remained above the waters, local media quoted Defense Ministry spokesman Won Tae-jae as saying.

But he said the video would not be disclosed to the public because there was no clue in the video to help determine the cause of the incident.

Meanwhile, President Lee Myung-bak paid a visit to the country' s northernmost island of Baekryeong, the closest island to the scene of the warship sinking, to inspect the navy's search operation.

Faced with mounting public criticism over the government, which has failed to give a clear explanation as to the cause of the incident, Cheong Wa Dae spokesman Park Sun-kyu said Lee's visit should not be interpreted as a political stunt.

Lee earlier in the day convened a Cabinet meeting, where he urged the authorities to conduct a scientific investigation into the naval incident to deter speculation.

"Since the incident happened at the frontline, the government should be thoroughly prepared to cope with any movement on the part of North Korea (DPRK). The armed forces are urged to maintain full alert without the slightest breach," Cheong Wa Dae said in a statement, suggesting that it does not rule out the possibility of the DPRK's involvement in the tragedy.