The state-run radio in Sri Lanka reported that Liberation Tigers of Tamil Eelam chief Velupillai Prabhakaran and his intelligence chief Pottu Amman are among those dead or missing in the December 26 tsunami disaster.
However, the rebels denied the report and termed it as 'mischievous' and 'fabricated'.
Sri Lanka Broadcasting Corporation, quoting Navy chief Vice-Admiral Daya Sandagiri had reported that Prabhakaran and Pottu Amman were among the tsunami casualties.
The LTTE, in a statement posted on its Web site, denounced the report.
"The LTTE and the Tamil people wish to strongly protest against this mischievous act of the Sri Lanka Broadcasting Corporation, stooping down to such low level of broadcasting news that (is) fabricated by interested parties," the statement said.
"At a time of a national catastrophe of this magnitude, it is very ... regrettable that a responsible media of the government takes upon itself the job of spreading rumours and speculation that tend to create confusion in the minds of the people."
The privately-owned 'Island' newspaper added to the speculation by reporting that a non-governmental organisation had smuggled an expensive coffin 'for a top LTTE leader', but did not give any names.
Over 30,000 people died in the tsunami devastation, which affected almost three quarters of the Sri Lanka's coast, including the north and east where the LTTE had key military bases.