The joint U.N.-Arab League envoy to Syria visited Turkey on Saturday for talks aimed at putting a lid on boiling diplomatic tensions between Damascus and Ankara.

Lakhdar Brahimi's visit comes amid growing concern that the civil war could spill over into Syria's neighboring countries and destabilize the region.

Brahimi met with Foreign Minister Ahmet Davutoglu, who warned that Turkey "will retaliate again if its border with Syria is violated again and if we feel that Turkey's national security is in danger."

Meanwhile, Syria issued a ban Saturday on Turkish civilian airlines flying over Syrian airspace "based on the principle of reciprocity," according to a Foreign Ministry statement. The move comes one day after Turkey itself announced it will divert its planes to avoid Syrian airspace because it considers it unsafe.

Syrian refugees in Turkey get food aid

The U.N. World Food Programme started an electronic food card program for the thousands of Syrian refugees who've fled to Turkey.

Each Syrian family will receive an electronic card with 80 Turkish liras, or $45, per family member per month.

"It allows Syrian families to shop and cook for themselves based on their own tastes and preferences," says Jean-Yves Lequime, WFP Emergency Coordinator in Turkey.

Turkey is currently hosting more than 93,000 Syrian refugees in camps. Turkish officials estimate an additional 40,000 to 50,000 unofficial refugees live in Turkey outside refugee camps.