>> Four times countries have said we will do this and four times it's been shredded. US Secretary of State John Kerry visibly out of patience facing off with his Russian counterpart Sergey Lavrov over the resumption of violence in Syria at the UN security council Wednesday.>> In other words, this is the moment of truth.
>> I think it's the most exasperated and sort of, angry John Kerry has been, arguably since he became secretary of the state.>> David Rohde has covered Kerry's diplomatic effort, for Reuters.>> This is really the last chance for the Obama administration to strike any kind of significant deal in Syria to stop the carnage, and it's failing.
Kerry's personally tried to work out a deal with the Russians for months, and months, and months now, and this is it, this is the moment, and it's just not coming together.>> We are in serious business here.>> The frustrations come after a UN humanitarian convoy was hit by an airstrike earlier this week.
The trucks carrying aid meant for civilians caught in Syria's five year civil war. The US says the bombing was likely carried out by Russian aircraft. Russia's denial of responsiblity sparking incredulity from Kerry.>> I listened to my colleague from Russia and I sort of felt a little bit like they're sort of in a parallel universe here.
e U.S. and Russia back opposing sides in Syria with Moscow allied with the regime of President Bashar Al-Assad. And the US, supporting a loose coalition of opposition fighters. A tentative ceasefire expired this week, and violence escalated despite Kerry's efforts at extending the truce. Kerry on Wednesday demanding Assad and Moscow ground their jets in areas where the UN is trying to deliver aid.