The top U.S. military officer says the U.S. has some insights into the activities of Islamic State militants within Syria, but he declined to comment Tuesday on the Obama administration's move to conduct surveillance flights over that country.

Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, told reporters in Kabul, Afghanistan, that the U.S. wants more clarity on the militants in Syria "as we craft a way forward."

U.S. officials say the military has begun surveillance flights over Syria, which could pave the way for airstrikes against the Islamic State militants who operate from safe havens there and have taken control of swaths of Iraq.

Dempsey has said he would recommend the military move against the Islamic State militants if there is a threat to the homeland.