Afghan violence: Seven troops die in two attacks
Seven soldiers serving with Nato's force in Afghanistan have been killed in two attacks, the alliance says.
An Afghan soldier turned his weapon on coalition troops in the western Farah province, reports said, killing two in the latest so-called insider attack.
Earlier, a roadside bomb killed five US soldiers in the southern Kandahar province.
The deaths came after three British troops were killed by a roadside bomb this week in southern Helmand province.
The Taliban launched its annual spring offensive last Sunday, saying it would target foreign military bases and diplomatic areas.
Some 100,000 soldiers are still serving with Isaf, but they are due to be withdrawn by the end of next year.
Nato is in the process of handing security operations to Afghan forces, and some areas have already been transferred.
'We stay committed'
The US-led International Security Assistance Force (Isaf) released a statement saying: "Two International Security Assistance Force service members were killed when an Afghan National Army soldier turned his weapon against Isaf service members in western Afghanistan today."
It did not disclose the nationalities of the victims, but unnamed American officials later said the victims were US soldiers, AP reported.
As the number of Nato troops killed by their Afghan counterparts continues to rise, analysts wonder how the breakdown of this relationship will have an impact on the scheduled departure of international forces from Afghanistan.
After the earlier roadside bomb in Kandahar, Isaf spokesman Brig Gen Gunter Katz said it had been a "difficult week" for the coalition, but added that the deaths would not change its commitment to the task in Afghanistan.
"Every soldier who dies here in Afghanistan is one too many," he said. "But again, this will not have an effect on our overall campaign. We stay committed and will stay committed in this country to support the Afghans also in the future."
Faisal Javi, a spokesman for Kandahar's governor, said the roadside bomb exploded in Mewand district, which has a strong Taliban presence, but he said the group had not yet claimed responsibility for planting the device.
Saturday's deaths bring the toll for coalition troops in 2013 to 49, including 37 Americans.
Most Nato troops are due to leave Afghanistan by the end of 2014 - when all combat operations are due to finish - although a small number will remain in support roles.