Four US servicemen and at least one Afghan soldier have been killed in two separate incidents in Afghanistan.
Three US soldiers died in clashes in the volatile eastern Kunar region, a spokesman said.
Another US soldier and an Afghan soldier were killed in a gun battle with Taleban fighters in southern Uruzgan province, an official said.
The country is seeing its bloodiest period since the fall of the Taleban in 2001, says the BBC Kabul correspondent.
Militants have recently stepped up their insurgency against government and foreign forces in the south and east.
Nato's International Security Assistance Force (Isaf) said the US soldiers were embedded with the Afghan army as trainers and "operating in support of the Isaf mission."
A coalition patrol was first struck by a homemade bomb and then came under attack from small arms and artillery fire in Kunar province, on the border with Pakistan, the US-led coalition said in a statement.
In Uruzgan, up to 150 Taleban fighters attacked a joint Nato-Afghan army convoy.
Three American soldiers were also wounded in the gun battle which last for four hours.
In recent weeks coalition troops have been pushing northwards into the remote mountains but the Taleban and their al-Qaeda allies have been hitting back.
On Thursday a coalition soldier was killed and another wounded in an ambush.
The US led coalition has been hampered by the rugged terrain and the ability of the insurgents to slip across Kunar's border with Pakistan into the tribal areas of the northwest frontier province to regroup, our correspondent says.
The latest violence came as the country celebrated 87 years of independence from Britain, which never fully colonised the nation but controlled its foreign affairs for years until 1919.