"Pentagon chief's statement could be described as 'final hysteria'. It only means a total failure, when someone loses his nerve and the only choice is to accuse the one who is effective in fighting terrorism, which is Russia," Yarovaya said in a statement.
Since 2011, Syria has been engulfed in a civil war, with government forces fighting against numerous opposition and terrorist groups, including Daesh, which proclaimed a caliphate on large territories in Iraq and neighboring Syria in 2014.
Russia started conducting aerial attacks against terrorists in September 2015, at the request of the Syrian government. A US-led coalition of dozens of countries has also been targeting terrorists in Syria with airstrikes since 2014, however with no permission from Damascus of the UN Security Council.