Thomas Jackson said he was sorry to the victim's family and to anyone who felt their right to "peacefully protest" had not been protected by authorities.
Many legal scholars say the White House lacks a legal justification for the strikes inside Syria. But the administration disagrees, saying its actions are covered by post-Sept. 11 legislation.
The U.S. and its allies are pursuing a new target in eastern Syria. A wave of airstrikes is being aimed at modular oil refineries controlled by ISIS. The revenue from those small refineries is believed to be helping ISIS finance its operations in the region.
Click the media player above to hear reporter Noel King in conversation with Marketplace Morning Report host David Brancaccio.