The US special envoy for the alleged war on Daesh terrorists in Iraq and Syria, is stepping down, officials say.

John R. Allen, the Special Presidential Envoy for the Global Coalition to Counter ISIL, will leave his position in early November, four US State Department officials told Bloomberg on condition of anonymity.

According to the officials, who were not prepared to publicly announce Allen’s departure, he has already let his superiors know he will step down.

Retired Marine Corps Gen. John Allen

Allen’s chief of staff, Karin von Hippel, will also quit to join a British think tank.

U.S. officials familiar with Allen’s decision say he has been frustrated with White House micromanagement of the war and its failure to provide adequate resources to the fight. He unsuccessfully tried to convince the administration to allow U.S. tactical air control teams to deploy on the ground to help pick targets for air strikes in Iraq,” said the Tuesday report.

Apart from support for the militants, the US military has also been leading a coalition to conduct airstrikes allegedly aimed at Daesh militants in Syria as well as Iraq since last year, despite which the Takfiris have gained ground in some of the regions.

This September 23, 2014 US Air Forces Central Command file photo shows a US Air Force F-15E Strike Eagle flying over northern Iraq after conducting airstrikes in Syria. (AFP)

Last month, the incoming Marine Corps Commandant, Lieutenant General Robert Neller, testified that the situation of the US fight was at a “stalemate” and the program to train militants there had yielded not more than four or five militants.

“John Allen has put his heart and soul into trying to make the president’s strategy work,” said Derek Harvey, a former senior military intelligence official who worked with Allen at US Central Command. “I have sympathy for the hard task he was given because I do not believe the president’s team was fully on board and he was never empowered to bring the leadership necessary to achieve the mission.”

Initially trained by the CIA in Jordan in 2012, the Takfiri militants have been carrying out horrific acts of violence, including public decapitations and crucifixions in areas under their control in Iraq, Syria and more recently Libya.