More than 50 intelligence analysts working at U.S. Central Command (CENTCOM) have formally complained to the Pentagon's watchdog that their reports on the Islamic State group (ISIS) have been repeatedly altered by senior officials to portray the war as being more successful than it actually is, reports The Daily Beast.

The complaints have prompted the Pentagon's inspector general to open an official investigation into the supposed manipulation of intelligence reports, which are prepared for several top U.S. policymakers including President Barack Obama.

"The reports were changed by CENTCOM higher-ups to adhere to the administration's public line that the U.S. is winning the battle against ISIS and al Nusra, al Qaeda's branch in Syria," according to the analysts, who are employed by the Defense Intelligence Agency but work at CENTCOM. The director of intelligence and his deputy in CENTCOM were implicated in the complaint.

Two senior analysts working at CENTCOM - which oversees the military operations in the fight against ISIS - filed a report with the inspector general in July after numerous internal complaints were ignored. About a dozen individuals told The Daily Beast that the complaint is backed by more than 50 additional analysts.

Some analysts allege that reports determined to be overly negative in their assessment of the ongoing war against ISIS never made it to their intended policymakers and were instead sent back down the chain of command or simply trashed. Other analysts say critical elements of their assessments were removed or altered so as to fundamentally skew their conclusions.

"But the complaint also goes beyond alleged altering of reports and accuses some senior leaders at CENTCOM of creating an unprofessional work environment," The Daily Beast reports. "One person who knows the contents of the written complaint sent to the inspector general said it used the word 'Stalinist' to describe the tone set by officials overseeing CENTCOM's analysis."

Despite ISIS's continued control of vast swaths of land in Iraq and Syria, the Obama administration's special envoy for the war, retired Gen. John Allen, has publicly touted the U.S.'s progress, saying in late July that the terror group's momentum had been "checked strategically, operationally, and by and large, tactically" and was "losing," reports The Hill. However, intelligence reports recently conducted by the CIA and Defense Intelligence Agency contradicted that assessment, saying the group is fundamentally no weaker than it was when U.S.-led bombings first began a year ago, according to The Associated Press.

CENTCOM spokesman Air Force Col. Patrick Ryder told The Daily Beast that while he couldn't comment on the specific investigation, "The Intelligence Community routinely provides a wide range of subjective assessments related to the current security environment. These products and the analysis that they present are absolutely vital to our efforts, particularly given the incredibly complex nature of the multi-front fights that are ongoing now in Iraq and Syria."