In Syria, the hard-won ceasefire deal is under severe strain -- after a series of deadly airstrikes, a nasty diplomatic dispute and a failure to deliver humanitarian aid.
Nearly a week after a ceasefire began-- airstrikes on a rebel-held neighborhood of Aleppo. But it was this attack on Saturday that may have pushed the truce to the brink of collapse.
A series of U-S airstrikes in the eastern city of Deir al Zour that left dozens of Syrian government soldiers dead.
The Pentagon said in a statement: "If we mistakenly struck a Syrian military position we regret doing so, especially the loss of lives. The coalition aircraft conducting the mission believed they were striking ISIL forces."
The Syrian government said more than 80 soldiers were killed and called the attack deliberate. Both Syria and Russia accused the U-S of underhanded support for ISIL, and other terror groups fighting the Syrian government.
"This hostile act from the U.S. is a very serious attack against Syria and its army, and it's crystal clear evidence of the support by the United States and their allies to the Daesh organization and other terrorist armed groups," said Bashar Ja'afari, Syrian ambassador to the UN.
"It is quite significant and frankly suspicious that the United States chose to conduct this particular air strike at this time," said Vitaly Churkin, Russian ambassador to the UN.
"After all they did nothing when ISIL was advancing on Palmyra. ISIL made a hundred mile march without being attacked by the coalition."
The suggestion that the U-S would cooperate with ISIL angered the U-S Ambassador to the United Nations.
"The Russian spokesperson came out and I believe somehow, thought we were complicit in even trying to protect ISIL. Really American citizens have been beheaded by this group, we are leading a 67 country coalition to destroy this group," said Samantha Power, US ambassador to the UN.
With the two countries that brokered the ceasefire -- the U-S and Russia -- engaged in a bitter squabble.It's unclear if they can still collaborate on key parts of the agreement -- like setting up a joint center to target ISIL and other terror groups.
Another key provision of the truce -- trucks full of humanitarian aid were to deliver supplies to Aleppo. But the convoys remain stuck at the Turkish border, waiting for a guarantee of safe passage.
