Aluminium fragments from a torpedo casing have also been found, Dong-A Ilbo newspaper quoted an unidentified member of a team investigating the blast as saying.
President Lee Myung-Bak hinted Tuesday that North Korea was involved in the March sinking of the Cheonan, which cost 46 lives. He promised a "resolute" response when the cause is established following the multinational probe.
The unidentified team member was quoted as saying the explosive traces were found on a funnel that was torn off the Cheonan by the blast on March 26 near the disputed border with North Korea.
"It has been confirmed that the explosive came from a torpedo," the team member was quoted as saying.
Detailed analysis of salvaged aluminium fragments also confirmed they are from a torpedo, the individual said.
The defence ministry denied the report. "No traces of explosive have been found," spokesman Won Tae-Jae said
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Putting principles before profits
Putting principles before profits
