Karuna Amman, leader of the LTTE's breakaway faction, has said the Tiger group headed by V Prabhakaran is "very weak" at present but it would not be possible to defeat it soon.
"The LTTE are now only maintaining a defence line. They can't launch any offensive. They are very weak now," Karuna said.
He, however added that it would take time for the Sri Lankan army to defeat the rebel outfit.
"It will not happen in the next few months. We have to work together to win this war," the former deputy to LTTE supremo Prabhakaran told the Sinhala language wing of BBC.
Amman, whose real name is Vinayamurthi Muralitharan, arrived in Sri Lanka earlier this week after he was deported from UK, where he served a prison sentence for immigration offences.
Karuna was sentenced to nine-month imprisonment in January after being convicted of identity fraud.
Karuna, who broke away from the LTTE in 2004, was arrested here in November last year for travelling on a diplomatic passport under a false name.
Sri Lanka government has repeatedly denied any assistance to him to leave the Island country for Britain.
On his arrival to Sri Lanka, Karuna appealed to all communities -- Sinhala, Muslim and Tamil, to help the government in defeating the LTTE, which he described as a 'brutal terrorist group'.
The founder of Tamil Makkal Viduthalai Puligal (TMVP) told BBC Sandeshaya he was 'very happy' that his deputy S Chandrakanthan alias Pillayan, was appointed as Chief Minister of the Eastern Provincial Council (EPC).