"France deplores this serious development," the foreign ministry said in a statement, adding that "all light must be shed" on what happened.

Iraqi officials labelled the strike a "blatant Turkish drone attack" in the autonomous Kurdish region, where Ankara has for weeks been raiding positions of the outlawed Kurdistan Workers' Party (PKK).

Two border guard battalion commanders and the driver of their vehicle were killed, the army said in a statement, marking the first Iraqi troop deaths since Turkey launched the cross-border operation in mid-June.

"France is deeply attached to full respect for Iraqi sovereignty," said the French ministry, adding that Paris "condemns any violation of this sovereignty."

France's statement is its latest expression of French anger against Turkey in an increasingly difficult relationship between the two NATO members.

President Emmanuel Macron has accused Ankara of violating the sovereignty of Greece and Cyprus -- claims Turkey rejects -- over maritime rights in the Eastern Mediterranean amid a scramble for gas resources.

Paris has also condemned Turkey's military intervention in Libya to support the UN-recognised Tripoli government while Macron has argued that unilateral moves by Ankara were contributing to the "brain death" of NATO.