Four Canadian soldiers were killed and six others were wounded during a major NATO offensive against insurgents in a volatile district in southern Afghanistan on Sunday.

"I am saddened to announce that four Canadian soldiers were killed during today's operations and a number of others were wounded" in the Panjwaii district, west of Kandahar, said Canadian Brig.-Gen. David Fraser at a news conference.

"All but one of the wounded is expected to return to their duties within the next few days."

Fraser offered his condolences to the families of the victims, but only two of the fallen soldiers have been identified:

• Warrant Officer Frank Robert Mellish
• Warrant Officer Richard Francis Nolan

Both are members of 1st Battalion, The Royal Canadian Regiment, based in CFB Petawawa in eastern Ontario.

They had been in the Canadian Forces for more than fifteen years and were veterans of several overseas missions. They also leave behind a spouse and children -- Nolan had three sons and one stepdaughter.

"I can tell you first and foremost that Frank and Rick were dedicated fathers to young boys, and I think that is what should define them -- that their core family values were extremely strong," said Maj. Peter Scott.

An official with NATO's International Security Assistance Force (ISAF) said the soldiers died when they were hit by enemy fire in fighting in Panjwaii district, west of the city of Kandahar.

Of the six wounded soldiers, two reportedly suffered light enough injuries for them to stay on in the combat area.

Fraser said that despite the deaths, the operation was a success.

According to ISAF, "more than 200 Taliban fighters have been killed since the beginning of operation Medusa early Saturday morning" in the Panjwaii district, said Fraser.

Further, he said more than 80 suspected Taliban fighters have been captured by the Afghan national police, and "an additional 180 insurgents were seen fleeing the district."

The major air and ground offensive -- dubbed Operation Medusa -- includes Canadian, British and American troops fighting alongside Afghan forces in Kandahar province.

The goal is to take control of the Taliban stronghold of Panjwaii, which covers an area roughly between 20 and 40 kilometres west of Kandahar city -- an area where Canadian troops have suffered casualties before, during heavy battles with Taliban insurgents in which at least six Canadians have died and 32 wounded.

"Despite these losses, Operation Medusa will continue,'' Fraser said. "ISAF is determined to remove the Taliban threat from this region."

Col. Fred Lewis, commander of the Canadian contingent, said he expected his troops to encounter fierce resistance from Taliban guerrillas during this mission.

"I think we're talking in the neighbourhood of hundreds" of fighters, said Lewis on Saturday. "Certainly not thousands, not tens. Might they just fade away? If they're smart, they will."

NATO said there were no reports of civilian casualties, despite the heavy bombardment in the area. However, Afghan defence officials said earlier that an uncertain number of civilians are dead after two days of fighting in the region.

A NATO statement said forces had gained ground during the operation, which was continuing Sunday.

McClure, the only reporter embedded with Canadian troops during the mission on Saturday, said commanders appeared confident during the heavy offensive.

"In the back of their minds, though, I think they knew that this was not going to be easy," said McClure.

The Taliban fighters "were well dug in, in their defensive positions in those vineyards, in the mud wall compounds and the verdant valley -- one of the rare bits of greenery you find here in Afghanistan -- and that it might come to tough house-to-house fighting, which Canadians have been trained to handle but haven't seen a lot of up until this recent tour."

He added: "As one soldier we're told said on the ground this morning shortly after the incident: 'We had our nose bloodied today."

With the latest deaths, 31 Canadian soldiers and one diplomat have been killed in Afghanistan since 2002.

The Canadian casualties come one day after NATO suffered heavy losses. Fourteen British soldiers were killed Saturday after a Royal Air Force Nimrod MR2 aircraft crashed about 15 kilometres west of Kandahar city.

Officials say the crash was caused by a technical problem, although the Taliban claimed its fighters shot down the plane with a Stinger missile.

The British Defence Ministry said the dead included 12 Royal Air Force personnel, a Royal Marine and an army soldier.

With a report by CTV's Matt McClure in Kandahar