Syria's foreign minister claims terrorists from more than 83 countries are killing soldiers and civilians across his country.
In a speech to the United Nations General Assembly, Walid Muallem compared their "invasion" to the September 11 attacks on New York.
"The people of New York have witnessed the devastations of terrorism, and were burned with the fire of extremism and bloodshed, the same way we are suffering now in Syria," he said.
"How can some countries, hit by the same terrorism we are suffering now in Syria, claim to fight terrorism in all parts of the world, while supporting it in my country?" he said.
The government accuses Turkey, Saudi Arabia, Qatar, Britain, France and the United States of arming, financing and training rebel forces in Syria.
Mr Moualem dismissed the idea that there are moderate rebels in Syria, which Western nations say are the ones they intend to support.
"The claims about the existence of moderate militants and extremist militants have become a bad joke," he told the assembly.
"Terrorism means only terrorism. It cannot be classified as moderate terrorism and extremist terrorism."
Mr Moualem also referred to video images on the Internet earlier this year of a rebel fighter eating what appeared to be the heart of a government soldier.
"The scenes of murder, manslaughter and eating human hearts were shown on TV screens, but did not touch blind consciences," he said.
"There are innocent civilians whose heads are put on the grill just because they violate the extremist ideology and deviant views of al Qaeda.
"In Syria ... there are murderers who dismember human bodies into pieces while still alive and send their limbs to their families, just because those citizens are defending a unified and secular Syria," Mr Moualem said.
