In November, the task force executed just under 300 airstrikes on ISIS targets in Iraq and Syria, compared with roughly 700 in October and about 1,500 in September, he said.
"From our point of view, it seems to us that ISIS are moving through regime areas with impunity" in eastern Syria while apparently fleeing to the west in an effort to reach territory controlled by other rebel groups fighting the regime of Syrian President Hafez al-Assad, British Army Maj.
In an interview with the Komsomolskaya Pravda daily, Gerasimov said that next year's developments in Syria will include "the completion of eliminating militants from Jabhat al-Nusra and its affiliates".
A two-star British general in the coalition's war against ISIS confirmed the "movement of limited numbers of ISIS militants westwards", but said the USA -led coalition won't pursue them because the area is operated by the regime.
"We've got no intention to operate in areas that are now held by the regime", Gedney said. "Right now we have not completed the defeat of ISIS [Daesh], and it would not be the time to leave".More news: Phoenix police shoot armed man after he charges at them
Washington has rejected similar Russian allegations in the past, saying US forces remain committed to killing off the Islamic State and denying it safe havens.
"Instead of the New Syrian Army, mobile ISIS groups, like a jack in the box, carry out sabotage and terrorist attacks against Syrian troops and civilians from there", he said, noting that while the pretext for the base's creation was "the need to conduct operations against ISIS" no information has been available to this respect during the first six months of its existence. "Our pursuit of these terrorists is as tenacious and determined as ever", he said.
"Our coalition will remain committed to the mission in Syria" until such time as political leaders decide otherwise, he said. "They are effectively training there", Gerasimov said, when asked about what's going on at the base.
"I would say that we've had a very successful 2017 in the military campaign", Gedney said.