Turkey's Foreign Minister Ahmet Davutoglu said on Tuesday the suspected chemical attack in Syria was a crime against humanity that must not go unpunished.
Davutoglu was speaking as Western nations appeared to be gearing up to launch military strikes on Syria over the attack near Damascus last week that activists say left hundreds of people dead.
"This is a very open violation of international law," he was quoted as saying by local media. "This is a crime against humanity. This crime against humanity cannot go unpunished."
He branded the chemical attack as "one of the biggest murders the modern age has ever seen".
"Turkey's number one priority is that the UN Security Council must take a joint stance on sanctions in the face of this crime against humanity," the foreign minister added.
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Davutoglu had said in remarks published Monday that Turkey would join an international coalition against neighbouring Syria even if the Security Council failed to reach a consensus.
Turkey -- the second biggest military force in NATO -- shares a 910-kilometre (560-mile) border with Syria.
Ankara has joined several Western governments in blaming the regime of President Bashar al-Assad for the toxic gas attack last Wednesday but Damascus has denied any responsibility.
Turkey, one of the most vocal critics of the Assad regime and one of the states most affected by the civil war on its doorstep, has stepped up diplomatic efforts with its allies to exert pressure on Damascus.
Davutoglu, who spoke with US Secretary of State John Kerry on Monday over the escalating crisis, is due to fly to Saudi Arabia Tuesday for talks with his counterpart there, his office said.
Turkey has taken in around 500,000 refugees from Syria as well as army defectors and has repeatedly called on the international community to act on the conflict that has now killed an estimated 100,000 people.