"We can only guess why it was needed to gather an emergency [UN Security Council] meeting in the middle of the weekend, although it is not hard to guess. Clearly, the West, headed by the United States which leads the coalition against Daesh is not speaking about al-Nusra Front in Syria, failing to meet its obligations," Lavrov said as broadcast on the NTV channel.
"The US Commander-in-Chief Barack Obama supported cooperation with Russia, as I was always assured. He himself confirmed this during a meeting with [Russian President Vladimir] Putin in China. Apparently, the military does not quite obey their supreme commander."
It is hard to fully trust the US-led coalition as it exclusively targets Daesh targets and avoids striking al-Nusra Front, Lavrov said.
"The US anti-terrorist coalition strikes exclusively Daesh and does not strike al-Nusra Front, although [US Secretary of State] John Kerry assures me every time that al-Nusra Front presents the same terrorist threat as Daesh. But they do not touch al-Nusra Front."
"I really do not know whom to believe. I definitely cannot believe them fully," Lavrov added.
However, it is yet too early to declare the failure of the ceasefire deal brokered by Russia and the United States in Syria, Lavrov said.
"At least we are committed to these agreements that have been reached in recent months and where a final point has been set."