Syria has been warned not to fly warplanes in areas where American troops are advising Kurdish and Arab forces fighting the Islamic State group, the Pentagon said on Monday. But it insisted this does not amount to a “no fly zone.”

Reporters pushed press secretary Peter Cook to explain the distinction.

“Our warning to the Syrians is the same that we’ve had for some time, that we’re going to defend our forces and they would be advised not to fly in areas where our forces have been operating,” Cook said.

“It’s not a ‘no fly zone,'” he added. Later, he said, “You can label it what you want.”

Twice last week the U.S. scrambled fighter aircraft to protect American special operations forces and partner forces after Syrian government warplanes flew near the northeastern Syrian city of Hassakeh. Cook said there have been no similar incidents since Friday.

“If need be we will send aircraft again to defend our forces,” he said.

Cook said the most recent warnings to Syria not to fly in areas near U.S. troops were communicated through the Russian military, which is operating in support of the Syrian government in its fight against opposition forces, including the Islamic State militants.

Asked whether the U.S. policy is to shoot down a Syrian or Russian aircraft if it poses a threat to U.S. troops on the ground, Cook said, “We’re going to defend our forces on the ground, absolutely.”

Cook was highly critical of Syrian military action in and around the divided city of Aleppo, which has become a main battlefield in Syria’s civil war. Relentless shelling and airstrikes have killed more than 300 civilians in the city since rebels broke through a government blockade of the opposition-held east on July 31.

“The Syrian regime aided and abetted by its allies, Russia and Iran, is driving the escalation with its indiscriminate bombing campaign,” Cook said. “Bombing densely populated urban areas, interrupting water and electrical services and maiming civilians is only adding fuel to Syria’s civil war and does nothing to degrade extremist groups, which was of course Russia’s original reason for its military intervention in Syria.”

(AP)