Russia and the United States clashed at the United Nations on Tuesday, accusing each other of supporting terrorism during a Security Council meeting convened over a sudden escalation of fighting in Syria.

Axar.az reports that citing Reuters, Deputy U.S. Ambassador to the U.N. Robert Wood called for a de-escalation of the fighting in Syria and the protection of civilians. He also expressed concern that the rebel offensive was led by Hayat Tahrir al-Sham.

"The fact that Hayat Tahrir al-Sham is listed as a terrorist organization by the U.S. and U.N. does not justify the further atrocities by the Assad regime and its Russian backers," said Wood, accusing Syrian President Bashar al-Assad's forces and Russia of causing civilian casualties in attacks on schools and hospitals.

In remarks directed at Wood, Russia's U.N. Ambassador Vassily Nebenzia said: "You were unable to summon the courage to condemn a clear terrorist attack undertaken against peaceful civilians in peaceful Syrian cities."

"There are no illusions that Washington will ever be willing to sincerely combat international terrorism," he said. "To be frank we are pleased that we are on opposite sides of the barricades right now from you."

Wood responded by accusing Nebenzia of being in "no position to lecture us on this issue" because Moscow "props up regimes that sponsor terrorism around the world."

"The United States has for decades fought the scourge of terrorism and will continue to fight that scourge of terrorism," he said.

It should be noted that the relative calm that has lasted for several years in Syria has come to an end. The insurgents have taken control of Aleppo and Idlib, launched an attack on Hama, and intense battles are ongoing with regime forces.