U.S. troops with the NATO-led force have shot and wounded five Afghan army soldiers in Kunar province, the Associated Press reported.
The troops had fired on what they suspected were militant forces, a NATO news release said.
The wounded Afghan soldiers were evacuated to a medical facility, it said.
"It is with deep regret that this incident has taken place; we have initiated an investigation to determine how
this happened and how to prevent any future occurrences," said Col. John Spiszer, a U.S. commander. "We have the utmost respect for our Afghan partners and value their relationship with ISAF."