Turkey's foreign minister said on Wednesday it was clear from television footage that chemical weapons had been used in an attack near the Syrian capital Damascus and telephoned U.N. chief Ban Ki-moon to urge an immediate investigation.
Syria's opposition accused government forces of gassing hundreds of people near Damascus by firing rockets that released deadly fumes over rebel-held suburbs, killing men, women and children as they slept. The Syrian government dismissed the allegation.
"Use of chemical weapons in Syria is evident from the footage coming from there," Turkish Foreign Minister Ahmet Davutoglu said in an interview on Kanal 24 television. "We have called for an immediate investigation by the U.N. teams."
The foreign ministry said in a statement Davutoglu had called U.N. Secretary General Ban Ki-moon to urge the Security Council to "carry out its responsibilities".
What would be the world's most lethal chemical weapons attack since the 1980s prompted an emergency meeting of the U.N. Security Council set for 1900 GMT.
"If these allegations are found to be true, it will be inevitable for the international community to take the necessary stance and give the necessary response to this savagery and crime against humanity," the foreign ministry said.
Ankara, once an ally of Syrian President Bashar al-Assad but now one of his fiercest critics, has long been concerned about the possible use of chemical weapons across its southern border.
Turkey began stepping up tests on casualties arriving from Syria for treatment earlier this year to determine whether they were victims of chemical weapons , but no details have been released publicly on the results of those tests.