Militants have killed two US soldiers and two Pakistani lorry drivers in attacks on bases in south-eastern Afghanistan, near the Pakistani border. A missile hit the US base at Shkin as troops were about to unload a transport helicopter, killing two. Eight people were also wounded in the attack. The drivers were shot dead as they left another US base at Spin Boldak. Taleban militants claimed both attacks, saying they meant to cut supply routes for US-led forces in the country. American warplanes were scrambled after the attack at Shkin, in Paktika province, but were unable to locate the attackers, the US military told AFP news agency. Nearly 150 US troops have been killed in Afghanistan since the start of the US intervention in late 2001 to overthrow the Taleban regime and its Islamist allies. Taleban spokesman Abdul Latif Hakimi told AFP that the militants had begun firing rockets at the Shkin base on Tuesday night, with the last one launched on Wednesday morning. A US military spokesman, Lt Col Jerry O\'Hara, confirmed that two soldiers were killed and eight \"military service members and civilians\" were wounded by what he called a mortar bomb. Police in Spin Boldak said they had arrested five people after the attack on the drivers, who had been leaving the base in a convoy after delivering fuel. Speaking for the Taleban, Mr Hakimi said anyone working for the US would be regarded as a target. (BBC)