Many US troops are deployed in southern Afghanistan
Seven soldiers have been killed in Afghanistan in the past 24 hours - four of them American and three Afghan.
Nato said three of the US soldiers died in southern Afghanistan on Sunday and the other in a bomb explosion on Monday in the east of the country.
This has been the deadliest year for foreign troops since the 2001 invasion.
President Barack Obama held two hours of talks with his war advisers on US troop levels, possibly his last meeting before taking a decision on the issue.
He is weighing a request from his top commander in Afghanistan, Gen Stanley McChrystal, for 40,000 more US troops to support the war effort.
Among the officials attending the evening meeting were Vice-President Joe Biden, Defence Secretary Robert Gates and Secretary of State Hillary Clinton, the White House said.
A US official said it would "possibly" be the last consultation before a new Afghan strategy was announced, though he cautioned that it was not something he could say "definitively".
In a statement released on Monday, Nato's International Security Assistance Force (Isaf) said that of those who died in southern Afghanistan, two US soldiers had been killed by a bomb attack and the other in a separate firefight with insurgents.
Three Afghan soldiers were also killed in a separate incident on Sunday by a roadside bomb in Helmand province, Afghanistan's Ministry of Interior said.
It said two other Afghan National Army soldiers had been wounded in the Musa Qala district by the same roadside bomb that had killed their three colleagues.
It added that six soldiers in Kunar province and one in Kandahar had been injured in incidents in the past 24 hours.
The ministry did not give any details of how the soldiers had been hurt.
As yet there has been no confirmation of any connection between the US and Afghan deaths.
Soldiers from more than 40 countries make up Nato's force of nearly 110,000, two-thirds of them from the US.
The biggest contingents operating in the west of the country are from the United States and Italy.