KANDAHAR, Afghanistan - Four Canadian soldiers, popular with their comrades who described them as "unsung heros," were killed Friday in two separate bombings in southern Afghanistan.

At least eight other soldiers were injured in the two attacks outside of Kandahar city.

Master Cpl. Scott Vernelli and Cpl. Tyler Crooks -- both of November Company, 3rd Battalion, Royal Canadian Regiment -- died in an explosion at about 6:45 a.m. local time in the restive Zhari district west of the city.

The company's deputy commander described the pair as well-rounded soldiers who filled a variety of jobs within the unit.

"They had all kinds of unsung hero-type jobs that they do that are not very glamorous because we put all of our focus on the platoon guys," said Capt. Kris Reeves, shortly after the bombing.

An Afghan interpreter was also killed and five other Canadian soldiers were wounded in the attack.

About two hours later, Trooper Jack Bouthillier and Trooper Corey Joseph Hayes, both of the Royal Canadian Dragoons, were killed in a roadside bomb blast in the Shah Wali Kot district northeast of the city, a region where the Taliban have stepped up attacks in the last few months.

Three other soldiers were wounded in that attack.

All of the soldiers were taking part in a major operation aimed at attacking Taliban command centres and supply lines, along a massive front stretching in an arc from the west to the northeast of Kandahar city.

The combined Canadian and American assault -- involving over 2,000 troops -- is the biggest land operation the two countries have conducted since the Korean War.

Brig.-Gen. Jonathan Vance, the commander of Canadian troops in Afghanistan, implored Canadians to remember that the soldiers believed both in the mission as a whole and in the jobs they were doing.

"Please do not think of this as a failure on the part of any person or of the mission itself," Vance said, reading a statement at Kandahar Airfield.

"Success in war is costly. We are determined to succeed so that Afghan lives improve, but the insurgents are equally determined to challenge and prevent Afghanistan from flourishing as the nation it so wants to be. Remember, the deaths of these superb Canadians occurred as Canadian Forces were bringing safety to those in peril. Today, they succeeded."

The deaths bring to 116 the number of Canadian soldiers who have died as part of the Afghan mission since it began in 2002.

In the attack on November Company, the blast could be faintly heard kilometres away at a Canadian forward operating base. Not long afterward, a platoon warrant officer gathered other senior officers to break the news.

Word spread quickly around the base.

Vernelli and Crooks were both well-known and popular with other soldiers in the company, which is on the cusp of finishing a six-month tour.

Both men were close with the commander of November Company, Maj. Rob McBride, who often joked with Crooks over the radio about sports.

"They were close friends of his," said Reeves.

Such was his respect for Crooks that McBride supported the young soldier as a candidate for officer training.

"He was getting ready to (be) on that path to be commissioned from the ranks," Reeves said. "He would have been good."

The bond McBride had with Vernelli, a veteran of a previous stint in Afghanistan, was just as strong.

The new father of a six-month-old girl was interested in returning to the battle-ravaged region, but wanted more of a challenge than being in one of the platoons.

"He wanted a role that he would be able to contribute and do something interesting and more hands on," Reeves said solemnly.

"So when he was deliberating whether he wanted to come back, the (officer commanding) got wind of that and said: 'Come back. Come back and we'll make this a really good tour."

Bouthillier was described by Vance as a fine athlete with a outstanding sense of humour.

The general also praised Hayes for his bravery.

"His friends remember him not only as a friend and a comrade in arms but a brother who inspired them to stand up in the face of danger and do what was right," Vance said in his statement.

Prime Minister Stephen Harper expressed his condolences behalf of the nation.

"The commitment to make Afghanistan a better place to live, demonstrated on a daily basis by the brave men and women of the Canadian Forces, is a testament to the values respected and revered by all Canadians," the prime minister said in a statement.

The offensive in which the soldiers died -- Operation Jaley -- has been ongoing over the last four days under a total news blackout.

The full battle group of the 3rd Battalion Royal Canadian Regiment -- backed by tanks, artillery and air support -- crossed the start lines around midnight March 17.

In Zhari district, soldiers marched on foot, crossing pitch-black poppies fields and three-metre deep streams -- known as wadis -- throughout that night.

One Canadian company approached from the north and one from the south in a squeeze-play manoeuvre meant to pin-down Taliban forces, while a full battalion of the famed U.S. 2/2 Infantry Regiment airdropped by helicopter into farmland west of them.

By daybreak they were in position to begin searching compounds and nearby fields for insurgent hideouts and bomb-making factories.

Canadian Leopard 2A6M battle tanks belonging to the Lord Strathcona's Horse regiment also rumbled in from the north, covering both NATO troops and an Afghan battalion that launched its own separate attack under the supervision of Canadian mentors.

"In all honesty, the point of the day was to go find a fight and we did," said Lt. Jeff Lloyd, who led November Company's 4 Platoon with the Afghans.

It was Lloyd's last mission before being rotated home.

The purpose of the late-winter assault was to hit Taliban staging points in advance of the spring fighting season, the annual bloody offensive of ambushes and roadside bomb attacks which begins soon after the poppy harvest ends.

The Taliban draws much of its fighting strength between May and October by tapping into southern Afghanistan's massive pool of unemployed farmhands.

Canadian soldiers uncovered a massive bomb-making factory at raid incompound, which had at least five booby traps laced throughout the structure.

Lt. Aaron Corey led his platoon metre by harrowing metre as they uncovered strings of command wires -- meant to set off the explosives -- throughout the mud-walled buildings.

In that incident all of the explosives were defused.