Whether or not the U.S. Central Command was sugarcoating intelligence to create the appearance of progress in the fight against Islamic State militants, the command's upbeat reports didn't manage to convince the rest of the intelligence community, current and former officials say.

The Pentagon's inspector general is investigating allegations that Central Command's top intelligence officials pressured analysts to discard parts of their work product that reflected poorly on the war effort in Iraq and Syria, resulting in flawed assessments that overstated American progress.

But the allegedly purposeful editing did not affect separate intelligence reporting by the CIA, the Defense Intelligence Agency and other agencies, and therefore did not undermine the government-wide intelligence assessment that the war is at a stalemate, the officials added. The CIA and other agencies have concluded that the Islamic State organization has been able to replenish its dead with a steady influx of foreign fighters and has not lost significant amounts of territory.

Still, the potential intelligence puffery may have influenced comments by certain key figures, say current and former officials, who spoke on condition of anonymity because they were not authorized to comment. For example, John Allen, the Obama administration's special envoy to the global coalition against the Islamic State, said in July that the Islamic State is "losing."

In his first public remarks about the allegations, Gen. Lloyd Austin, commander of U.S. Central Command, told the Senate Armed Services Committee on Wednesday that he welcomed the investigation but could not comment directly until the review was over. He vowed to take "appropriate action" if the investigation concludes that intelligence reports were inappropriately altered.

"I assure you that we will do everything in our power to make sure that the whistleblowers remain protected and that there is no retaliation," Austin added.

The general emphasized that none of the Central Command intelligence reports would have been sent directly to President Barack Obama.

A former Central Command official confirmed a report by the Daily Beast website that more than 50 intelligence analysts had complained that their conclusions were undercut. One or more senior analysts from the command made a written complaint to the Defense Department inspector general in July, prompting an investigation that officials have publicly acknowledged.

The Associated Press reported in July on the broad U.S. intelligence assessment that the campaign had not fundamentally weakened the Islamic State's hold on large parts of Iraq and Syria, and that the inflow of foreign fighters was replenishing the group's losses.

The CIA estimates the number of Islamic State fighters at between 20,000 and 31,500, double to triple the estimate from 2014.

Reports in recent months by Central Command's intelligence operation, run by Maj. Gen. Steven Grove and his civilian deputy, Greg Ryckman, told a rosier story, current and former officials say. The former Central Command official, who has spoken to many of the players involved, said Ryckman made it known that he wanted assessments to reflect what he felt was the campaign's effect in degrading the Islamic State.

Spokesman Patrick Ryder said neither Grove nor Ryckman was available for comment.

When analysts didn't agree, they found their sources challenged and their well-grounded analysis edited out, the former official said.

"It's not that they changed what went into the products — they took out things that didn't fit the narrative," the former official said.

Many of the analysts work for the Defense Intelligence Agency, but they were assigned to Central Command and were part of that chain of command. The DIA has its own separate intelligence assessment that tracks the more sober view of the rest of the intelligence community, officials say.

The intelligence reports emerged from the command's Joint Intelligence Center, which produced daily briefs and two- to three-page analyses that were distributed to other intelligence agencies and occasionally the White House.

It's hardly unprecedented for a combatant command running a military campaign to have a more positive view of its effectiveness than intelligence agencies, which tend to take a pessimistic line.

Gen. David Petraeus, for example, famously feuded with the CIA about progress in Iraq in 2007, and later Afghanistan in 2010. In both cases, he was commanding the war effort and disputing assessments that the campaigns weren't going well.

But there was no allegation that Petraeus changed intelligence assessments. In some cases he won the right to include a dissenting view.

Sen. John McCain, R-Ariz., said the committee was "disturbed" over the allegations that Central Command officials "skewed intelligence assessments to paint an overly positive picture of conditions on the ground. ... If true, those responsible must be held accountable."

Asked about the matter at an intelligence conference last week, DIA Director Lt. Gen. Vincent Stewart said there are often disagreements about intelligence assessments, within and between agencies.

"We pride ourselves on analytic rigor, in which we look at the vast amount of information to deliver an assessment," he said. But he added: "It is not science. It is as much experience and judgment as anything else. So when we go through the analytic process, it is a pretty rough-and-tumble debate."

He said that the inspector general's "investigation will play itself out (and) figure out if we did something wrong, and we will be better as a result."