Deputy foreign minister Faisal Mekdad warned on Thursday that Syria's air force could destroy any Turkish warplanes used in a threatened assault on the war-torn country.
"We warn that the Syrian Air Force is ready to destroy Turkish air targets in the skies of Syria," Mekdad told reporters, according to Syria's official SANA news agency.
"We warn the Turkish leaders that if they start fighting in the region of Afrin, it will be seen as an aggression by the Turkish army against the sovereignty of Syria," he added.
Afrin is among the areas Turkey has said it will attack in northern Syria to target the Kurdish People's Protection Units (YPG) militia.
Ankara accuses the YPG of being a branch of the outlawed Kurdistan Workers' Party (PKK) that has waged an insurgency in Turkey since 1984.
The US-led coalition fighting the Islamic State group said at the weekend it was working to create a 30,000-strong border security force in northern Syria.
Ankara immediately objected, fearing the new force would be comprised of the YPG.
President Recep Tayyip Erdogan said this week that Turkey had to "nip this terror army in the bud".
The United States later insisted it does not intend to create an army or conventional border guards.
Erdogan said on Monday that Turkey would soon begin an operation against towns in Syria controlled by Kurdish militia, calling the areas "nests" of terror.
"Tomorrow, (or) the day after, (or) within a short period, we will get rid of terror nests one-by-one in Syria starting with Afrin and Manbij" in northern Syria, he said in a televised speech.
Warnings of fallout after US freezes funding for Palestinian refugees
The UN agency for Palestinian refugees warned Wednesday it faced its worst funding crisis ever after the White House froze tens of millions of dollars in contributions, a move Palestinian leaders decried as cruel and blatantly biased.
The agency provides Palestinian refugees and their descendants across the Middle East with services including schools and medical care, but Prime Minister Benj … read more