First inspections of the bow of a South Korean warship show it was hit by an outside impact of considerable force, a military official said yesterday, as suspicion increasingly falls on North Korea.

The Cheonan sank and was split in half after a mystery blast on March 26 close to the disputed border of the two Koreas, leaving 40 sailors confirmed dead and six others still unaccounted for.

Seoul has been careful not to point the finger directly at the North over the incident in the Yellow Sea, which has stoked already tense ties, and Pyongyang has denied it was to blame.

However, the South's Yonhap news agency last Thursday quoted a senior military source in Seoul as saying it was suspected that North Korean submarines attacked the ship with a heavy torpedo.

Yesterday, salvage teams took their first look at the bow section after it was hauled to the surface a day earlier, finding another body and more evidence a strong external blast was to blame.

Quoting an unidentified military official, Yonhap said initial inspections confirmed a large iron gate was off its hinges and a chimney was missing.

"This means there was a strong impact from the outside," the official said.

A Joint Chiefs of Staff spokesman told AFP they expected to find more bodies in the bow, which was to be towed ashore later yesterday for detailed inspections to find extra clues as to what tore the vessel apart.

The stern was salvaged on April 15 but offered few ideas as to what had caused the explosion, from which 58 sailors were rescued.

South Korean Defence Minister Kim Tae-Young said a mine or torpedo may have sunk the corvette, but his ministry said it would keep an open mind until the investigation is completed.

Pyongyang has accused the South's "war maniacs" of seeking to shift the blame for the tragedy to the North.

The communist North on Friday seized South Korean-owned assets at a mountain resort, warning that the two countries were on the brink of war over the sinking.

And yesterday the North warned it was prepared to use nuclear weapons if it was invaded by the United States and South Korea.

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