The bodies of four Canadian soldiers killed in a roadside bomb attack in Afghanistan over the weekend began their final journey home Monday.

The flag-draped caskets of  Cpl. Randy Payne, Cpl. Matthew Dinning, Bombardier Myles Mansell and Lieut. William Turner are tentatively expected to arrive at CFB Trenton, Ont., between 6 p.m. and 7 p.m. on Tuesday.

The four soldiers died Saturday when a roadside bomb detonated under their lightly armoured G-Wagon jeep as they travelled from Gumbad to Kandahar -- a journey of about 75 kilometres.

They were returning from a goodwill mission to a northern village.

More than 3,000 coalition troops, including Canadians, Americans, Britons, Australians, Dutch, French, Romanians and Estonians, lined the runway for Monday's send-off ceremony at Kandahar airfield.

With a bagpiper solemnly in lock-step behind them, pallbearers took the four caskets up the ramp of a waiting Hercules transport aircraft for the flight home.

"Into your hands Lord, we humbly entrust our brothers," intoned Captain David McLeod, a Roman Catholic padre with the Canadian Forces.

"In this life you have raised them with your tender love. Deliver them now from every evil."

Once aboard the aircraft, Canadian Brigadier-General David Fraser, the coalition commander in southern Afghanistan, held his own private farewell.

Two of the soldiers killed in Saturday's improvised explosive attack were part of Fraser's protection force, which he affectionately called his "posse."

Fraser had also been on the goodwill tour to Gumbad on Friday, but he returned by helicopter Friday night.

Dinning, Mansell and Turner all died at the site of the explosion -- a dried-up riverbed.

Payne, the fourth soldier, died later of his wounds in hospital.

The attack was the worst one-day combat loss for the Canadian army since the Korean War.

Filmmaker Richard Fitoussi was travelling around 15 metres behind the soldier's vehicle when the bomb went off.

"As soon as the bomb went off I turned the camera on and I started capturing the reaction of what happened," Fitoussi told Canada AM Monday.

"I really don't know how to articulate my reaction. I feel bad. These guys had kids and wives and there's going to be a lot of families that are going to be going through some hard times."

CTV's Sarah Galashan, reporting from Kandahar, said it had been "a very hard couple of days for everyone on base."

"These soldiers absolutely believed in what they were doing in their mission," she said.

"The ceremony was very emotional ... it was very powerful."

Flag debate

Outside coalition headquarters in Kandahar Monday, the Canadian flag flew at half-mast.

However in Ottawa, the Canadian flag remained at normal station above the Parliament buildings.

The new Conservative government has said it won't follow the Liberals' tradition of lowering the flag to half-mast every time a Canadian soldier is killed.

In a letter to The Globe and Mail Sunday, Defence Minister Gordon O'Connor scrambled to defend the decision.

O'Connor said his government is returning to a tradition that the Peace Tower flag is lowered only once a year, on Remembrance Day.

"The previous Liberal government broke with this long-standing tradition ... and instead decided on an ad-hoc basis to lowering the flag of the Peace Tower," O'Connor wrote in the letter.

"As Minister of National Defence, I can tell you that this adhockery unfairly distinguished some of those who died in Afghanistan from those who have died in current and previous operations."

Earlier reports indicated that O'Connor and General Rick Hillier, Chief of the Defence Staff, are likely to be at CFB Trenton on Tuesday when the caskets arrive.

Prime Minister Stephen Harper is not expected to be there.

Turner, a Canada Post letter carrier stationed in Edmonton, and Mansell, a carpenter, were two of the more than 400 reservists currently serving in Afghanistan.

Fifteen Canadian soldiers and one diplomat have died in Afghanistan since 2002.

An investigation has been launched into this latest attack.