UN Secretary-General Ban Ki-moon has expressed alarm at reports coming from the Syrian flash-point city of Homs that suggest Syrian government forces are arbitrarily executing, imprisoning, and torturing people.
Ban told the 193-member UN General Assembly that the Syrian government has failed to protect its people.
Syrian UN Ambassador Bashar Ja'afari took to the podium to respond to Ban, telling the assembly that international pressure on his country is politically driven.
Ja'afari added that Ban was not "duly informed" about the true situation in the country and reiterated that the Syrian opposition was comprised mostly of terrorists groups.
Turkey's foreign minister, Ahmet Davutoglu, added Ankara's condemnation of Syrian actions, calling the current operations "an organized massacre campaign run by a regular army against its own people."
Earlier, the International Committee of the Red Cross told Syria it was unacceptable that its aid convoy had been prevented from entering a district of Homs that was devastated by government bombardment and where the opposition said President Bashar al-Assad's army had committed a massacre.
The convoy has been blocked since arriving in Homs on March 2.
Ban issued a plea after it became clear the convoy couldn't deliver the humanitarian supplies, urging Damascus to let the aid shipment through.
Syrian activists said on March 3 that troops continued to shell districts in Homs as government troops kept the Red Cross convoy out.
Residents in in Baba Amr, a western neighborhood of Homs that was overrun this week by army troops, describe conditions there as catastrophic. No water, electricity, or new food has reached the district since it was besieged by troops more than three weeks ago in a prolonged battle with rebel forces inside.
The rebels retreated from Baba Amr and other districts on March 1, saying they were low on ammunition and that humanitarian conditions in the neighborhood made it impossible to stay longer.
Meanwhile, activists said on March 3 that heavy clashes had erupted between Syrian government troops and rebels in the province of Idlib near the border with Turkey. There were no immediate reports of casualties.
In Washington, U.S. presidential spokesman Jay Carney condemned the Assad regime's latest actions, saying "the brutalities they carried out in the last 24 to 48 hours [are] disgraceful."
Turkish Foreign Minister Davutoglu said during a press conference with his visiting Italian counterpart that "The recent incidents in Baba Amro and those that took place in Zabadi before that, and previous incidents in other cities, have become an organized massacre campaign run by a regular army against its own people. The tension and violence increases each day."
"The Syrian regime is committing crimes against humanity every day," Davutoglu added. "Now, as the international community we need to get united and stand up for international values. Preventing the delivery of humanitarian aid, rejecting the entry of UN representatives and humanitarian aid organizations to Syria is another crime."
Foreign diplomats meanwhile received the bodies of U.S. journalist Marie Colvin and French photographer Remi Ochlik, who were killed during recent shelling of Baba Amro. A representative from the Polish Embassy, which manages U.S. affairs in Syria, received Colvin's body, while French Ambassador Eric Chevallier received the body of Ochlik. The bodies were turned over from Al-Assad University Hospital in Damascus, where they had been brought by the Syrian government from Homs.
With Reuters and AP reporting