John Kerry Makes Impassioned Plea at United Nations for Syria Cease-Fire

— -- U.S. Secretary of State John Kerry made an impassioned plea in front of the United Nations Security Council today for all sides in the Syrian conflict to live up to their obligations under a cease-fire agreement. The move may be the best chance for the U.S. to help bring an end to the violence, humanitarian crisis and displacement of thousands of Syrians.

Kerry's determination to restore the cease-fire comes in wake of the most flagrant yet of the violations: Two days ago, a United Nations humanitarian aid convoy headed to opposition-held areas of Aleppo was destroyed in a prolonged airstrike.

"On Monday, 20 aid workers were killed in an outrageous, sustained, two-hour attack directed at a fully authorized humanitarian mission near Aleppo — fully authorized," Kerry told the Security Council this morning. "All of the permits had been given. Everybody was on notice."

U.S. officials believe Russian aircraft, not Syrian, were responsible for the strike but have yet to publicly accuse Moscow. Yesterday the White House said it could have been only Russians or the Syrian regime and that either way, Russia is accountable for the strikes, given its leverage over Syria and its commitments under the cease-fire.

In spite of all this, rather than abandon the cease-fire, Kerry today urged the Syrian regime to adhere to its terms, calling for the grounding of all regime aircraft.

"Our purpose in this negotiation was to put an end to the kind of horrific and indiscriminate attacks that have been the primary cause of fear, of suffering, of displacement," Kerry said. "And under our plan, all of this could be quickly accompanied by serious negotiations between the parties, aimed at a political transition and a conclusion to the conflict."

Meanwhile, the Russians have released a series of conflicting statements in an effort to justify the strike on the U.N. convoy. They suggested at one point the convoy was accompanied by an armed opposition vehicle and most recently suggested the strike might have been carried out by a U.S. drone flying in the region. The U.S. Defense Department quickly denied that, saying it doesn't fly aircraft over that area of Syria.

Moscow has yet to respond to Kerry's request to ground all regime aircraft, but negotiations will likely continue through the rest of the week at the U.N. General Assembly in New York. Members of the International Syria Support Group are expected to convene again in the coming days.

"The future of Syria is hanging by a thread, and I urge this council not to give up," Kerry said today. "And I urge the entire international community to get behind the best chance that we have yet had to reduce the violence, to provide humanitarian assistance and to open up the space for negotiations."