Master, a former spokesman of the LTTE, has been under interrogation in Colombo, the capital, since crossing the government line from the combat zone 10 days ago.
He said: "The propaganda by the LTTE was that these people died because of military shelling by government forces.
"They forcibly recruit children even if it is just one child in a family ... When the children were taken the parents attacked the recruiters and they [rebels] retaliated by beating the parents."
'Children forcibly recruited'
Chater said it was impossible to verify whether the interview was conducted under duress or to challenge Master's claims.
The UN has accused the LTTE of conscripting child soldiers, including the 16-year-old daughter of one of its own staff.
Chater said that in footage released from pro-rebel Tamil websites and TV stations, heavy shelling inside the conflict zone is shown.
He said it was impossible to verify when the pictures were taken.
The Sri Lankan army insists its forces only use small arms fire in what they still describe as a "hostage rescue mission".
In an interview conducted by the Associated Press news agency by email, a Tamil Tiger political chief denied holding Tamil civilians as human shields and said the rebels would not surrender.
The rebel chief said the fight for a separate Tamil state would continue regardless of what happens on the battle field.
Fighting between the rebels, who are seeking a separate state, and the Sri Lankan government has been raging for months.
Mahinda Rajapakse, the Sri Lankan president, has said the government will not halt its offensive against the rebels, despite calls from the EU and aid organisations to do so.
He said on Thursday: "We have no plans to go for a ceasefire with the Tigers [and] they have a little time left to drop their weapons and surrender."
His comments came a day after the foreign ministers of Britain and France, David Miliband and Bernard Kouchner, visited the island to push for a truce and aid agency access to civilains trapped in the conflict zone.
The president said he would not bow to international pressure for a ceasefire, and promised he would work to "rescue" Tamil civilians.
The UN estimates that up to 50,000 civilians are trapped in the fighting along the island's northeast coast.
According to the UN as many as 6,500 civilians may have been killed and another 14,000 wounded in the government's offensive against the LTTE so far this year.
The government has blocked most aid agencies from working in the north, and has put civilians who are escaping the fighting into camps guarded by the military.
Aid workers who have visited the camps have testified to food shortages, lack of sanitation, a desperate medical situation and chronic overcrowding.
Although the LTTE has been condemned for using civilians as human shields, the UN says both sides in the conflict may be guilty of war crimes.