An Afghan soldier killed three British service members with gunfire and a rocket-propelled grenade in the dead of night, a betrayal that highlights the difficulties in rapidly building up Afghan security forces so that foreign troops can go home.
The soldier fled after carrying out the attack in southern Afghanistan early Tuesday, leaving his motive unclear. But the Taliban claimed that he was a militant sympathizer who was taken in by insurgents after the assault — one which could further weaken support in Britain for an unpopular that has now taken the lives of 317 Britons.
In London, Prime Minister David Cameron condemned the killings as "appalling" but insisted the incident should not change NATO's strategy of working alongside the Afghan army. Four other British service members were wounded in the attack on a base in Nahr-i-Saraj district of Helmand province that is home to members of the 1st Battalion Royal Gurkha Rifles.
It was the second time in eight months that an Afghan turned against British troops partnering with local security forces. In November, an Afghan policeman killed five British soldiers at a checkpoint in Helmand.
Afghan police in the past have also attacked American soldiers and their own police stations, though such intentional attacks are rare.
Still, Tuesday's attack comes at a time when the international coalition is ramping up training of Afghan soldiers and policemen so they can ultimately take responsibility for securing and defending the nation. The speed with which Afghan security forces are growing — the allies set an interim goal of expanding the Afghan army from 85,000 in 2009 to 134,000 troops by October 2011 — has raised concerns about infiltration by the Taliban and the professionalism of the recruits.
It remained unclear how long Tuesday's attacker had been enlisted in the Afghan National Army, whether he plotted the assault with others and what motivated him to carry out the killings — which Britain's Ministry of Defense called a "suspected premeditated attack."
Lt. Col. James Carr-Smith, spokesman for the coalition task force in Helmand province, said: "We believe these were the actions of a lone individual who has betrayed his NATO and Afghan comrades. His whereabouts are currently unknown, but we are making strenuous efforts to find him."
There were few details about how the attack unfolded.
The British Defense Ministry said the Afghan soldier used "a combination of weapons."
He fired a grenade from a shoulder-mounted launcher at British soldiers inside a base control room, Afghan Defense Ministry spokesman Gen. Mohammad Zaher Azimi said.
In a message posted on its website, Taliban spokesman Qari Yousef Ahmadi said the Afghan soldier first opened fire with a machine gun on "soldiers who were sleeping" at the base about 1 a.m., according to a translation of the message by SITE Intelligence Group. The Taliban claimed eight British soldiers died, not three as the Afghan government and international coalition reported.
The Taliban said the soldier then "fired inside the enemy base," causing a blaze that destroyed ammunition and weapons. The message said the "heroic soldier" fled to a known Taliban location where he was received by insurgents, "who appreciated his work and took him to a safe place."
Afghan President Hamid Karzai sent a letter of apology to the British government. Afghan Army Chief of Staff Gen. Sher Mohammad Karimi expressed regret and pledged to capture and prosecute the attacker. "The loss of any of our coalition partners affects us deeply," Karimi said.
Cameron has said he wants the country's 10,000 troops out by the time of Britain's next election, which must be held by 2015. Support for the war, initially strong, has fallen as the casualty rate has increased among troops based in Helmand, a center of the Taliban insurgency.
"This is not typical of the Afghan National Army," Cameron said. "This is a rogue element. ... We must not let this change our strategy of building up the army, building up the government of Afghanistan."
The attack came one day after NATO Secretary-General Anders Fogh Rasmussen warned that waning political support for the war could encourage the Taliban to carry out even more attacks on coalition forces.
"The Taliban follow the political debate in troop-contributing countries closely," Rasmussen said Monday in London, where he was meeting with Cameron.
Lt. Gen. Nick Parker, deputy commander of the NATO-led forces, said that while it was important not to draw too many conclusions before a full investigation is conducted, the attack represents a "really serious breach of trust."
"Our Afghan partners have got to look very carefully at what's happened and they've got to reassure us that they are doing everything they can to minimize it happening again," Parker said.
Still, Parker said the vast majority of Afghan security forces were "real, genuine partners" and that partnering the forces is a key to the eventual exit of foreign forces. "We have got to transfer security responsibility to the people whose country this is and if we don't do that, we're not going to succeed in our mission," he said.
Mark Moyer, research director of Orbis Operations, a counterinsurgency consultancy in McLean, Va., said he did not think the incident would have a major impact on the partnering strategy.
"Our commanders generally recognize the great value of working alongside Afghan soldiers, who can interact with the population and collect information better than Americans can," Moyer said. "These incidents are very small in number given the tens of thousands of foreign troops who are partnered with Afghan forces."