Three American military personnel and three civilians died early Friday in a single-car crash in Mali's capital, U.S. officials said.
U.S. Africa Command said in a statement that the cause of the crash remains under investigation.
In Washington, a U.S. defense official said one of the three Americans was from U.S. Army Intelligence and Security Command, and the two others were assigned to U.S. Special Operations Command.
The official spoke on condition of anonymity because the deaths had not been officially announced.
The military personnel were in Mali as part of a U.S. special operations training mission that was suspended after last month's coup overthrew the country's democratically elected president.
In recent years, the U.S. military has been helping train Malian troops in counterterrorism tactics to fight al-Qaida-linked militants who have established bases in Mali's northern desert.
Associated Press writer Robert Burns in Washington contributed to this report.