"What is now happening in Aleppo and around it - we warned the Americans about this in advance," the minister said. "The U.S. knows that we will be providing air support to the Syrian army to prevent territories from being seized by terrorists."

According to the minister, Russia will be making decisions regarding operations by its air group in Syria proceeding from its vision of the situation and there should be no surprises for the United States in that respect.

"In a telephone conversation I told US Secretary of State John Kerry that the United States has for many months defaulted on its obligation to separate the opposition groups loyal to it from Jabhat al-Nusra (outlawed in Russia as a terrorist organization)," Lavrov said. "Unable of doing that the United States has been saying all the time that the positions of "good" and "bad" opposition groups are mixed and it has been asking us and the Syrian leadership to postpone air strikes."

"We believe that since last February there has been more than enough time for the normal opposition to separate from the terrorists (the ceasefire took effect in Syria on February 27)," he said. "All those who have not distanced themselves from the terrorists have nobody to put the blame on but themselves. I explained that to John Kerry very clearly and emphasized the absolute need for the Americans to comply with another promise of theirs - to take action to prevent infiltrations of militants and weapons from Turkey."