The deaths have come in volatile southern Helmand province in the past nine days amid a new offensive to uproot Taliban fighters. Seven years after British forces first deployed to Afghanistan — and after the loss of 185 troops — ex-military chiefs are criticizing tactics and equipment, while members of the public wonder about the benefit of taking part in the conflict.

Defense Secretary Bob Ainsworth and Prime Minister Gordon Brown claim that Britain's role in Afghanistan is crucial to root out extremist terrorists who could potentially attack the United Kingdom and to prevent a tide of Afghan heroin from reaching British streets.

Brown said Friday that the war is vital to Britain's security.

"There is a chain of terror that runs from the mountains and towns of Afghanistan to the streets of Britain," he told reporters at the G-8 summit in L'Aquila, Italy. "Having talked to President (Barack) Obama and the rest of the world leaders, there is a recognition that this is a task the world has got to accept together and this is a task we have got to fulfill."

Michael Clarke, head of London-based military think tank the Royal United Services Institute, said public concern is mounting and urged politicians to be more honest about Britain's initial reasons for joining the 2001 invasion.

"What they won't really say is that it's about the credibility of the NATO alliance, and our military relationship with the United States," Clarke said.

Some critics say that Britain should either withdraw from the mission, or that troops must be provided with better equipment, including more helicopters. Britain, the United States and Canada have long complained that they have engaged in heavy fighting in Afghanistan while some European nations have shied away from combat roles.

Tony Philippson, whose son James was killed in Afghanistan in 2006, said the public remained skeptical about whether foreign troops will ever be able to suppress the Taliban and bring peace to the country.

"I've always felt it was a risky business, and I think it's still on a knife edge about whether they can succeed," Philippson told the BBC.

Gen. Charles Guthrie, the head of Britain's military between 1997 and 2001, said he believes British soldiers have died as a direct result of a shortage of helicopters for troops in Afghanistan. British troops are suffering heavy casualties from roadside bombs, and a lack of helicopters mean soldiers must make more journey across Helmand by road.

"If there had been more, it is very likely fewer soldiers would have been killed by roadside bombs," Guthrie — a longtime advocate of higher defense spending — was quoted as telling the Daily Mail newspaper.

Britain's defense ministry declined to disclose how many helicopters Britain has in Afghanistan on security grounds, but said additional aircraft are being sent to support the mission.

The ministry said that the two latest casualties died in separate incidents Thursday. The bloodshed has intensified as Afghans prepare for elections planned for next month.