A suicide bomber penetrated a foreign army base in Afghanistan to kill eight US CIA employees yesterday, one of the spy agency's largest death tolls, and a separate attack killed four Canadian troops and a journalist.
A "well-dressed" Afghan army official detonated a suicide vest at a meeting of CIA officials in southeastern Khost province, Taliban spokesman Zabihullah Mujahid told Reuters.
"This deadly attack was carried out by a valorous Afghan army member when the officials were busy gaining information about the mujahideen, in the (fitness) club," he wrote in an email.
The attack is one of the most ambitious of the war, highlighting the Taliban's reach and coordination at a time when violence has reached its highest levels since the overthrow of the Taliban regime by US-backed Afghan forces in 2001.
It was also the second Afghan army killing in as many days on the foreign troops and officials who are meant to be mentoring them, casting a shadow over plans to bolster the Afghan army and police to allow their troops to eventually bring them home.
US President Barack Obama is sending 30,000 extra troops to tackle the violence and Nato allies are contributing thousands more. An Afghan army official said on Wednesday that Washington had pledged $16 billion to train the army and air force.
When asked how the attacker managed to launch an assault in a foreign military base, Taliban spokesman Mujahid replied: "Since the man was an officer, he had not much difficulties."
US officials said the dead Americans were CIA employees. Some people were also wounded in the explosion, defence officials said, but no US or Nato troops were among them.
The CIA has been expanding its presence in the country, stepping up strikes against Taliban and al-Qa'ida militants along the border between Afghanistan and Pakistan.
Forward Operating Base Chapman, the site of the suicide attack, is near the Pakistan border, in one of the areas of Afghanistan where the Taliban insurgency is strongest.
The agency's role hunting terrorism suspects in Afghanistan has been criticised by both Afghans and human rights groups.
The five Canadians - four soldiers and a journalist - were killed when their armoured vehicle was hit by a bomb in southern Kandahar province, the Canadian Defence Ministry said.
The blast, about 4 km (2.5 miles) outside Kandahar, struck the patrol as it was visiting community reconstruction projects.
The Khost base targeted by the suicide attacker is also a centre for reconstruction projects, a key part of Obama's strategy to stabilise the country.
Washington has pledged a "civilian surge", adding hundreds of US experts to support work on development projects that aim to undermine support for the Taliban and other insurgents.
But foreign aid agencies warned earlier this year that the shift into the military bases, and the use of military personnel to carry out development projects, risked a dangerous blurring of the boundaries between troops and civilians.
The journalist killed was Michelle Lang, 34, on assignment for the Canwest News Service. She was on her first assignment in Afghanistan and had been in the country since 11 December.
She is the third journalist to die in Afghanistan this year.
The attack brought Canada's military deaths in Afghanistan to 138. Canada has a 2,800-strong military mission in Afghanistan, but the mission has become increasingly unpopular at home and it is scheduled to be withdrawn at the end of 2011.