A NATO airstrike killed five Afghan soldiers on Thursday in a deadly friendly-fire incident.
The International Security Assistance Force said in a statement that the Afghan troops were killed accidentally in Logar province, and that the incident was under investigation.
Western officials quickly apologized for the attack Thursday, and Karzai did not immediately condemn it.
“This attack, NATO has admitted to me they did it mistakenly. We will investigate the issue and then speak about it," Karzai said, according to The Associated Press.
The Afghan president added, however, that he would speak much differently — and likely in harsher tones — addressing his own country’s media.
ISAF said the aircraft that shot the Afghan soldiers was performing reconnaissance when it “engaged suspected insurgents on a ridge.”
“It was later determined that the suspected insurgents were Afghan National Army soldiers,” the ISAF statement said, according to The Washington Post.