Just after the occurrence of the case the south Korean authorities asserted that the ship's sinking near the Paekryong Island had nothing to do with the military drills that were waged in the sea west of the Thaean Peninsula of South Chungchong Province.

A soldier witness wrote in his written statement that he heard an exploding sound and saw a white flash from where the Paekryong Island is located at the time of "Cheonan's" sinking. He later said that a warship fired shells from Tumunjin northwest of Paekryong Island. It is only recently that this fact was made known to the public

"It sounded boom as to shock me," he wrote, adding "I heard the fire of our battleship from Tumunjin that day and the one I heard at 21:23 sounded more loudly."

According to the daybooks on the joint military exercises procured by the media, there were the naval maneuvering and supply drill from 11:00 to 13:00 and naval anti-special war unit operational drill from 14:00 to 21:00 that day.

It was also revealed that the south Korean puppet navy patrol ship "Sokcho," which fired shells toward the north soon after the sinking incident, was carrying out its guard operation in waters where it was on duty.

"As there is fresh doubt about the case, the Ministry of Defense is required to disclose not only the firing exercise in Tumunjin that day but only the information about Foal Eagle military drill and other facts", said the secretary general of the Citizen's Solidarity for Democratic Society.