The US is due to deploy an additional 30,000 troops in Afghanistan
Six international soldiers have been killed in Afghanistan, Nato officials say, making Monday the deadliest day for foreign troops there in two months.
Three Americans and a British soldier were killed in the south and a French soldier died north-east of Kabul.
The nationality of the sixth soldier has not yet been released.
The deaths came as a poll commissioned by the BBC and others showed most Afghans are increasingly upbeat about the state of their country.
Of more than 1,500 Afghans questioned, 70% said they believed Afghanistan was going in the right direction - a big jump from 40% a year ago.
The Americans died in a clash with militants during an "operational patrol" in southern Afghanistan, US military spokesman Col Wayne Shanks said.
AFGHAN POLL FOR BBC
70% believe Afghanistan is going in right direction
68% back the presence of US troops
62% back the presence of Nato troops
90% want country run by the current government
69% believe Taliban poses biggest danger to the country
A British soldier serving with a bomb disposal team in the Musa Qala area of northern Helmand Province died after an explosion, the UK Ministry of Defence said. His family has been informed.
France said one of its soldiers had been killed and another wounded while patrolling with Afghan troops in Alasay, a valley largely under militant control.
"A non-commissioned officer paid with his life for the commitment of France to the peace and security of the Afghan people, and an officer was very gravely wounded," a statement from President Nicolas Sarkozy's office said.
Nato said one other soldier had died in eastern Afghanistan.
The BBC's Mark Dummett, in Kabul, says the latest casualties bring the death toll for foreign troops in Afghanistan this year to 15.
It suggests that 2010 will be just as bloody - if not more so - than last year, which was the deadliest for international forces since the US-led invasion in 2001.
The high death toll is partly because insurgents have changed their tactics and are using more powerful bombs, our correspondent says.
But it is also because foreign troop numbers are rising, he adds.
President Barack Obama announced last month that an additional 30,000 US troops would be deployed quickly in Afghanistan to fight the insurgency.
The reinforcements will take the total number of US troops in Afghanistan to more than 100,000.
In a recent interview on US TV, the commander of US forces in Afghanistan, Gen Stanley McChrystal, said the troops surge was having the desired affect and the tide was turning against the Taliban.
The insurgency is largely concentrated in southern and eastern Afghanistan, but analysts say it is moving to the previously calm north and west.
On Sunday, an American service member and two Afghan road construction workers were killed in separate attacks in southern Afghanistan.
Earlier this month, a suicide bomber killed seven CIA agents at America's Forward Operating Base Chapman near the eastern Afghan city of Khost.