Afghanistan bomb: 3 British soldiers killed were on patrol in armoured Mastiff sent to protect troops from IEDs Trusted: The heavily-armoured Mastiff, the newest in the range of protected patrol vehicles being used for UK operations, was introduced in 2009. Here, it is compared with the 'Snatch' Land Rover The dead soldiers served with the Royal Highland Fusiliers, 2nd Battalion, the Royal Regiment of Scotland (2 SCOTS). Their identities have not been released, but the Ministry of Defence said their next of kin had been informed. Major Richard Morgan, spokesman for Task Force Helmand, said: 'It is with deep sadness that I must confirm that three soldiers from The Royal Highland Fusiliers, 2nd Battalion The Royal Regiment of Scotland, have died after their vehicle was struck by an improvised explosive device in the Nahr-e Saraj district of Helmand Province. Their deaths come as a great loss to all those serving in Task Force Helmand. Our thoughts and prayers are extended to their family and friends at this difficult time. Scotland`s First Minister Alex Salmond said: 'This is tragic news and our thoughts and deepest sympathies are with the families and loved ones of the soldiers who have been lost. This incident demonstrates once again the dangers faced by our armed forces, often on a daily basis, and they deserve our deepest gratitude and respect for the job they do in some of the most difficult and trying circumstances imaginable. No words can truly bring comfort to the families at a time like this, but the thoughts and prayers of everyone in Scotland will be with them upon hearing this dreadful news. 'Paying a high price': It is the biggest single loss of life inflicted by a buried bomb since six soldiers died when their Warrior armoured vehicle (above) struck an IED in March last year Overdue: The MoD's other main armoured vehicle, the Warrior, was heavily criticised by a coroner five years ago for not having enough protection. Improvements were finally made in June 2011 About 350 soldiers from the Royal Highland Fusiliers, 2nd Battalion The Royal Regiment of Scotland (2 SCOTS) were deployed to Afghanistan in March to start a six-month operational tour of Helmand. The battalion, based at Glencorse Barracks in Penicuik, Midlothian, took over a number of roles including mentoring and training Afghan National Security Forces, to help prepare them for when Nato troops pull out next year. They are advising Afghan police chiefs and assisting with the training of new officers. Poppyscotland, which raises funds to support ex-servicemen and women, posted on its Facebook page: 'We're deeply saddened to hear that three members of the Royal Highland Fusiliers, the 2nd Battalion The Royal Regiment of Scotland have been killed in Afghanistan. Our thoughts are with their families and colleagues. It was unclear last night whether the explosion was caused by the British vehicle hitting the bomb or whether it had been triggered by someone monitoring for the patrol. Officials said they had not seen an increase in Taliban activity in the area. Reaction: Prime Minister David Cameron told ITV's Daybreak today that the UK had paid a 'very high price' for the work it was doing in Afghanistan The horrific incident happened around midday Afghan time yesterday as the troops took part in a mission in the district of Nahr-e Saraj South, an insurgent hotbed. A convoy was understood to be helping search for IEDs close to the border with Kandahar Province when the blast struck one vehicle. The attack also killed nine Afghans. The heavily-armoured Mastiff, the newest in the range of protected patrol vehicles being used for UK operations, was introduced in 2009. Carrying two crew and eight troops, the vehicles are trusted because no-one has been killed in them - despite several striking roadside bombs. A defence source said: 'A very big IED struck the Mastiff, a huge one. The vehicle was thrown high up in the air, overturned and came down the wrong way up. It is a very well protected vehicle, but if the insurgents build a bomb big enough they can take anything out. Scene: The soldiers were on a routine patrol in the Nahr-e Saraj district of Helmand Province The Taliban last night claimed responsibility for the attack, threatening to step-up bombings against Coalition troops in the 'coming months'. The insurgents warned they would infiltrate enemy ranks to conduct 'insider attacks' and target military and diplomatic sites with suicide bombers. In past years, spring has marked a significant upsurge in fighting between the Taliban and NATO forces along with their local allies. This fighting season is a key test, however, as the international coalition is scheduled to hand over security responsibilities to Afghan forces next year. UK forces have dramatically cut back on foot patrols in recent months remaining mostly in their bases while Afghan troops have taken over the role as the British soldiers prepare for the withdrawal of thousands of servicemen and women next year. The change of operational policy has led to a significant reduction in casualties. Until yesterday, three servicemen had died this year in Afghanistan compared to 15 in the same period in 2012 and 16 in the first four months of 2011. A very big IED struck the Mastiff, a huge one. It is a very well protected vehicle, but if the insurgents build a bomb big enough they can take anything out Defence source Each mission of a 'fighting patrol' now has to be cleared high up the chain of command. However, vehicle patrols such as the one yesterday by UK troops on main roads have continued. The British deaths come a day after seven crew were killed when a U.S. civilian cargo plane crashed at Bagram airbase, near the Afghan capital Kabul. It also came just two weeks after the new brigade arrived in southern Afghanistan for what is expected to be the last bloody summer offensive. Commanded by Brigadier Rupert Jones, the son of Colonel 'H' Jones who won the Victoria Cross at Goose Green in 1982, his soldiers of 1st Mechanized Brigade officially took command on 10th April. The formation which has the Rifles, Royal Highland Fusiliers, Duke of Lancasters and Royal Regiment of Scotland as its lead infantry units, is expected to serve a longer tour as units prepare to pull out. The Royal Highland Fusiliers are split across Helmand and have a company based in Nahr-e Saraj, a mortar platoon based in Lashkar Gah and they also run the Lashkar Gah Police training centre. As the UK Area of Operation decreases with the handover of Forward Operating Bases to Afghan Security Forces, the number of bases occupied by British troops has reduced from 37 to 12. Meanwhile, in another attack in the south of the country, a roadside bomb in the Shah Wali Kot district of Kandahar province killed three civilians and wounded five. And in Archi district in the province of Kunduz, a roadside bomb killed two people, including a local police commander who had been credited with reducing the number of insurgent attacks in his area. VIDEO: David Cameron reacts to soldier deaths Britain's 444 victims of 12-year battle with Taliban insurgents A total of 444 British troops have been killed in Afghanistan since Western forces invaded the country in 2001 in response to the September 11 attacks. In addition, more than 2,000 American troops and over 600 soldiers from other countries in the Nato coalition have died as a result of fighting with the Taliban. The latest deaths bring the total of British casualties in 2013 so far to six, all in the dangerous Helmand Province which is often considered a Taliban stronghold. Blown up: The deaths of (top row left to right) Sergeant Nigel Coupe, Corporal Jake Hartley, Private Anthony Frampton and (bottom row left to right) Private Christopher Kershaw, Private Daniel Wade and Private Daniel Wilford in March last year was the biggest-ever single loss at the hands of insurgents Sapper Richard Walker was killed in January in a 'blue on green' attack from a rogue member of the Afghan National Army. Kingsman David Shaw died weeks later when his checkpoint came under fire from insurgents - he was airlifted back to the UK for hospital treatment, but did not survive. In March, L/Cpl Jamie Webb, 24, from Wythenshawe, Greater Manchester, died after an attack by Taliban militants in the Nad-e Ali district of Helmand. Last year, six British servicemen were killed when a roadside bomb struck their armoured vehicle. The attack was the worst single loss of life for UK troops in Afghanistan since a Nimrod crash killed 14 in 2006. The deaths of Cpl Jake Hartley, 20, Pte Anthony Frampton, 20, Pte Christopher Kershaw, 19, Pte Daniel Wade, 20, Pte Daniel Wilford, 21, and Sgt Nigel Coupe, 33, was the biggest-ever loss at the hands of insurgents. While many parts of the country remain unsafe, the rate of British casualties has been slowing as Western troops have gradually pulled out of their operations in Afghanistan. All combat forces are due to leave by the end of next year, when security will be handed over to the Afghan army and police.