Bob Ainsworth: "The way forward is hard and dangerous - more lives will be lost"
A British soldier has become the seventh to die in a week of fighting in Afghanistan, as a minister warned "more lives will be lost".
The serviceman, from the Light Dragoons, died in an explosion near Gereshk in Helmand Province on Tuesday night. Next of kin have been informed.
Defence Secretary Bob Ainsworth said "for Britain to be secure, Afghanistan needs to be made secure".
The latest death takes the number of soldiers to die in Afghanistan to 176.
Another British soldier who died on Monday in a helicopter crash in Afghanistan's southern Zabul Province has been named as Captain Ben Babington-Browne, 27, from Maidstone in Kent, who served with 22 Engineer Regiment, Royal Engineers.
He added: "More lives will be lost and our resolve is going to be tested... Success will be achieved incrementally."
He said Afghans would eventually take responsibility for their security but said: "This is not going to happen tomorrow, or in a few short weeks or months.
"If we are to succeed we need both courage and patience to see it through. There is no defined end date, only an end state".
He said that there were "compelling reasons" for the UK's commitment to the operation.
"If we leave now the Taliban will take control and al-Qaeda will return."
The BBC's security correspondent Frank Gardner says politicians are struggling to overcome a "credibility gap" because most of the public does not understand Britain's long-term intentions in Afghanistan.
Describing it as a mission to root out al-Qaeda does "not hold water", he says, because the terror group's bases are in Pakistan not Afghanistan.
The soldier who died on Tuesday was part of Operation Panther's Claw, a major assault against the Taliban.
Lieutenant Colonel Nick Richardson, spokesman for Task Force Helmand, said: "This soldier gave his life for the security of his own country and the freedom of the Afghan people -there is no greater sacrifice than this.
"Our deepest and heartfelt sympathies go to his family and loved ones."
Under fire in Helmand with the BBC's Ian Pannell
The Light Dragoons, based in Norfolk, are among 700 UK troops taking part in Panther's Claw, launched two weeks ago in Helmand.
A much larger offensive in the province is being fought by about 4,000 US and 650 Afghan troops.
The joint campaign is designed to drive the Taliban out of the region and make it safe for presidential elections due next month.
Earlier Mr Ainsworth told the BBC there was "gloom and worry" about the death toll but also a "sense of momentum" about the operation.
He rejected comparisons with the Vietnam conflict, which lasted more than 15 years and cost the lives of nearly 60,000 US servicemen.
Mr Ainsworth said: "I don't accept that. We have made considerable progress."
He added: "There is, of course, gloom and worry back here in London with the numbers of people that we've lost. If people weren't [worrying], there would be something seriously wrong with them.
"But when you go out to Afghanistan, as I did last weekend, there is a very real sense of momentum."
Mr Ainsworth's comments come shortly after a steep rise in UK casualties in Afghanistan.
The seven deaths this week alone include Lieutenant Colonel Rupert Thorneloe, the commanding officer of the 1st Battalion Welsh Guards, who became the most senior Army officer to be killed on operations since the Falklands War.
He and Trooper Joshua Hammond, from the 2nd Royal Tank Regiment, were killed after an improvised explosive device (IED) exploded near their vehicle.
Opposition parties claim personnel in Afghanistan are still being hampered by a shortage of equipment.
Shadow defence secretary Liam Fox said: "The bottom line from our troops is they don't have enough armoured vehicles and they don't have enough helicopters. The government needs to act."
Dr Fox also said the government needed to be pragmatic about what it could really achieve in "a very broken 13th century country".
"If we can get it broadly stable, if we can get Afghanistan able to look after its own internal and external security, if we can get reasonable governance, I think at that point we can say that we've done a good job," he added.
Mr Ainsworth said: "We don't want to stay for a day longer than is absolutely necessary."
BRITISH CASUALTIES IN AFGHANISTAN MARCH 2006 - JULY 2009
September 2006: Highest monthly toll with 19 dead including 12 killed when a RAF Nimrod crashes in Afghanistan.
June 2008: British death toll reaches 100. Among the 13 fatalities in June is the first British female soldier.
May 2009: Surge in casualties as Taliban use powerful Improvised Explosive Devices to attack British forces.
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