Migrants are escorted from the MV Sun Sea at CFB Esquimalt in B.C. on Friday. Letters purportedly written by some migrants deny any involvement with terrorism. (Jonathan Hayward/Canadian Press)

Letters purportedly written by two of the roughly 490 migrants who arrived in B.C. aboard a cargo ship deny any involvement with terrorism and claim they are fleeing "mass murder" in Sri Lanka.

The Canadian Tamil Congress, which distributed the two letters on Monday, said they were written by two Tamil journalists on board the MV Sun Sea and contain the "opinions expressed" on behalf of the migrants.

The letters claim the ethnic Tamil population in Sri Lanka still faces harsh treatment since the end of the bloody, decades-long civil war between government forces and separatist rebels.

"We would like to ask the Canadian people and the Canadian government to have faith in us to believe that we are innocent civilians who have been affected by the conflict," one letter obtained by CBC News says.

"We are not terrorists. We would also like to let you know that we will abide and live by the laws of this country."

The letters also dispute the Sri Lankan government's claims that the civil war has come to an end, insisting there are "widespread occurrences of disappearances, mass murders and extortion."

The MV Sun Sea as seen before it was escorted into a B.C. harbour. (DND)

"We have travelled for almost four months with much suffering and pain," one of the letters says.

"We have come here, to this wonderful country Canada, to protect ourselves and our family members from the murders, disappearances and violence that still exist in our native country."

The Sri Lankan government insists there is "complete peace" in the country following its victory last year over the Tamil rebel group, the Liberation Tigers of Tamil Eelam (LTTE), also known as the Tamil Tigers. Sri Lanka also claims it went out of its way to minimize civilian casualties during its final advance on rebel-held territory in early 2009.

The Tamil Tigers were outlawed in Canada as a terrorist group in 2006 for their use of child soldiers and suicide bombers during the country's 25-year civil war, which killed an estimated 70,000 people.

The ship's passengers include more than 50 women and 50 children. Immigration officials were expected to begin detention review hearings on Monday in Vancouver for the migrants, who arrived in B.C. aboard the cargo ship on Friday.

Vessel fitted to 'maximize profits': Toews

Meanwhile on Monday, Public Safety Minister Vic Toews said the vessel had been extensively renovated to "maximize profits" by accommodating a large number of passengers.

Speaking to reporters in Winnipeg, Toews said the MV Sun Sea was well equipped with sanitation systems to accommodate the migrants for a long voyage.

"It's not simply 500 people getting onto a boat and coming here as a last-minute thought," Toews said.

The setup of the vessel suggests a "broader criminal enterprise" involved, including the Tamil Tigers, the minister said.

The minister noted it was "relatively cheap" to purchase and outfit a ship in the current global economy, which made such methods "very profitable" to human smugglers and traffickers.

Evidence also suggests the vessel was a "test boat" intended to gauge the response of the Canadian government, Toews added, but he would not comment on the number of other ships believed headed for Canada.

Despite media reports saying the Sun Sea was turned away from Australia, the intention of the operators of the vessel was always to come to Canada, he said.

The arrival of the ship has stirred an emotional debate in Canada. Many people have wondered why the ship was not turned back, while others have accused the migrants of jumping the immigration queue to hasten their bid for Canadian residency.

Sri Lankan government officials have also chided the Canadian government for not turning away the Sun Sea, saying the money paid to the smugglers by the migrants will go toward the Tamil Tigers' efforts to regroup.

As a signatory to the UN Convention on Refugees, Canada is obliged not to send migrants back to their own country if they face persecution there.

Last October, 76 Tamil migrants who arrived in a boat off Vancouver Island claimed refugee status, saying they were fleeing persecution. All were eventually released from custody after allegations that some were linked to the Tamil Tigers were not proven.