General John Allen, the US Special Presidential Envoy for the Global Coalition to Counter the Islamic State, leaves the office.
The decision is reported to have been taken given disagreements in the Barack Obama's Administration policy on the Islamic State fight.
Allen was disappointed with inadequate efforts of Washington to fight the IS. He is to leave the office in some weeks.
Derek Harvey, a former senior US military intelligence official said that, Allen "was never empowered to bring the leadership necessary to achieve the mission".
At the same time, the White House representative explained Allen's leave with his personal grounds, particularly the health of his wife, who suffers from an auto-immune disorder.
Russia may lead a new coalition, which will comprise Iran, Syria, and Hezbollah, and manage to tackle the extremists. Beside that, Russia intents to build-up its presence in the Mediterranean, according to a new military doctrine.
As Pravda.Ru reported, the Stratfor military analyst Sim Tack claimed that Russia has always aimed to use diplomatic methods to settle the conflict in Syria, and is the main peacekeeper in the region.
Read article on the Russian version of Pravda.Ru