美国空军基地遭塔利班袭击
Four US soldiers have been killed in Afghanistan, hours after the US announced direct talks with the Taliban.
在美国宣布要与塔利班进行直接对话数小时之后，四名美国士兵在阿富汗被杀。
US forces have been stationed at Bagram since 2001 (file image)
A spokesman for the Taliban said the militant group was behind the attack at Bagram airbase.
Bagram, near the Afghan capital Kabul, is the largest military base for US troops in Afghanistan.
A condition for the talks, due to begin on Thursday in Qatar, was for the Taliban to renounce violence.
The soldiers were killed by "indirect fire" from insurgents at the airbase, US officials said.
Taliban spokesman Zabihullah Mujahid said the militants had launched two big rockets at Bagram.
The BBC's Jonathan Beale says the attack is a reminder that a ceasefire has not been made a precondition to the talks, scheduled to start on Thursday.
It also highlights the difficulties that may dog the negotiations with an insurgency which is far from unified, our correspondent adds.
Trust 'low'
In comments made before the news of the attack emerged, US President Barack Obama said the announcement of talks was an "important first step toward reconciliation".
The talks are set to take place in Doha, Qatar, where the Taliban have just opened their first official overseas office.
US officials said prisoner exchanges would be one topic for discussion with the Taliban, but the first weeks would mainly be used to explore each other's agendas.
Afghan President Hamid Karzai said his government was also sending delegates to Qatar to talk to the Taliban.
Also on Tuesday, Nato handed over responsibility for security for the whole of the country to Afghan security forces.
International troops are to remain in Afghanistan until the end of 2014, providing military back-up when needed.
As well as renouncing violence, other conditions of the talks are that the Taliban break ties with al-Qaeda and respect the Afghan constitution - including the rights of women and minorities.
Talks between President Karzai's High Peace Council and the Taliban are due to follow a few days after those between the US and the Taliban, officials say.
The level of trust between the Afghan government and the Taliban is described as "low".
In the past, the Taliban have always refused to meet President Karzai or his government, dismissing them as puppets of Washington.
Masoom Stanekzai, secretary of the High Peace Council, would not give a specific date for their talks but said they would take place "within days".
US officials stressed that this was the first step on a very long road, adding that there was no guarantee of success.