KABUL (AFP/Reuters) - Nato announced Saturday that two more US soldiers had been killed in an attack in Afghanistan, bringing to five the total American deaths in the conflict in the last 24 hours. The Nato-led International Security Assistance Force (Isaf) had already announced the deaths of three US soldiers Friday in bomb blasts in southern and eastern Afghanistan, where foreign military fatalities are at record levels. An Afghan soldier on guard at a joint base with US troops shot dead two American servicemen and wounded two others as they slept, a provincial official said on Saturday. Shahedullah Shahed, spokesman for the governor of Wardak province west of Kabul, said the shooting took place after a combined team of Afghan and US forces had returned from a joint operation late on Friday. "The Americans were in the middle of sleep when an Afghan soldier on duty opened fire on them," Shahed said. "We have no clue as to why he shot them." A statement from Nato-led forces said two American soldiers died from injuries suffered in a "hostile attack" in eastern Afghanistan on Friday. A press officer for the Western troops said he could give no further details of the incident. This year, 386 foreign soldiers, including 228 Americans, have been killed in Afghanistan, according to figures on the independent www.icasualties.org website, the highest in a year since the 2001 US-led invasion. On Saturday, the police chief of northern Kunduz province Gen Abdul Razaq Yaqubi, said a motorcycle packed with explosives went off in Imam Sahib district, killing three civilians and seriously wounding six others, including a police officer. The district governor, Juma Khan Bawar, said the dead comprised two men and a child and that 20 civilians were wounded. Afghan National Army (ANA) Gen Mohammed Zazai said his troops and US special forces killed four Taliban and arrested one wounded militant in an operation in the Chahar Chino district of southern Uruzgan province on Friday. A similar operation on Saturday in Sangin district of southern Helmand province killed three Taliban, he added.