Here's Pentagon press secretary Air Force Brigadier General, Pat Ryder:

"US commanders assessed that the UAV, which was now less than half a kilometer from U.S. forces to be a potent threat and US F16 fighters subsequently shot down the UAV in self-defense at approximately 11:40 local time. It's important to point out that no U.S. forces were injured during the incident. We have no indication that Turkey was intentionally targeting U.S. forces.

(FLASH)

Turkey is one of our strongest and most valued NATO allies and that that partnership continues and will continue. So this is certainly a regrettable incident."

This video showed smoke rising from various sites thought to have been targeted by Turkey in a Kurdish-controlled region.

A Turkish defense ministry official said the drone shot down by the coalition did not belong to the Turkish armed forces, without saying whose property it was.

U.S. support for Kurdish forces in northern Syria has long caused tension with NATO ally Turkey, which views them as a wing of the outlawed Kurdistan Workers' Party (PKK), the group which claimed Sunday's attack in Ankara near government buildings.

Separately, aerial footage released by Turkey's National Intelligence Agency on Thursday showed various drone attacks on what it said were Kurdish targets in Syria.

Reuters could not independently verify the claim, location and date the videos were shot.