NATO officials in Kabul say three U.S. troops were killed Sunday in eastern Afghanistan.
Officials say a homemade bomb struck a U.S. patrol and then insurgents ambushed the troops with gunfire.
Another three U.S. troops were killed in skirmishes Saturday in the southern part of the country.
A French soldier and two unidentified troops NATO officials said were not Americans were also killed Saturday in militant attacks.
The nine deaths at the start of August follow the deadliest month for international forces since the U.S.-led invasion to fight the Taliban and al-Qaida in late 2001.
Some 4,000 U.S. Marines and several hundred Afghan forces are operating in southern Afghanistan's Helmand province -- a remote militant stronghold that has largely resisted central government control.
The offensive in the south marks the first major operation under U.S. President Barack Obama's revamped strategy to defeat an increasingly violent Taliban insurgency.
Separately Saturday, Afghan officials said suspected Taliban militants ambushed a convoy carrying Afghan President Hamid Karzai's campaign staff, killing one guard and wounding two other people. Mr. Karzai was not with the convoy.
Mr. Karzai has led Afghanistan since the U.S.-backed invasion in 2001. He won the 2004 presidential election and is seeking a second term in his country's August 20 election.
Some information for this report was provided by AFP, AP and Reuters.