An Iraqi forces member looks at a crater made by an air strike in western area of the city of Mosul, where an intense battle is being waged against the Islamic State. (Aris Messinis/AFP/Getty Images)

The Pentagon has struggled in recent weeks to effectively explain what lies behind a surge in reported civilian casualties in its air campaign against the Islamic State, fueling speculation that the new Trump administration is pursuing policies resulting in a greater loss of life.

Military officials insist there has been no significant change to the rules governing its air campaign in Iraq and Syria, and ­instead attribute the string of alleged deadly incidents to a new, more intense phase of the war, in which Islamic State fighters are making a final stand in densely populated areas such as the Iraqi city of Mosul.

But some in Iraq and Syria are left wondering whether the higher death count is a product of President Trump’s bare-knuckle military stance and his suggestions that the United States should “take out” militants’ families.

The recent incidents, and the attention surrounding them, have generated concern within the military that the strikes have undermined the United States’ ability to fight the Islamic State.

“It does have a negative impact on our image at least throughout the region and the world, and it’s probably detrimental to the strength of our coalition. And that’s exactly what ISIS is trying to target right now,” Col. Joseph Scrocca, a military spokesman, said in a recent media briefing. ISIS is a common acronym for the Islamic State.

The military’s difficulty in accounting for the civilian casualties — exacerbated by classified regulations and a complex process for airstrikes — has allowed the Islamic State to advance its own version of the events. The group has accused the United States of killing hundreds of residents of Mosul and decried what it has said are “continuous ­American-Iraqi massacres” in that city and elsewhere.

“We’re ceding space to the adversary who wants to create the perception of disregard for civilian life,” said David Deptula, a retired Air Force general who heads the Mitchell Institute for Aerospace Studies.

Incidents that have been brought up by rights groups include a March 17 strike on a crowded building in Mosul that may have killed at least 140 people and a March 16 strike in the vicinity of a Syrian mosque. Both attacks are under investigation.

The surge in reported casualties in March was so dramatic that it prompted Airwars, a respected watchdog group, to suspend its tracking of Russian air operations in Syria — known to take a devastating toll on civilians — to focus on U.S. actions.

Since U.S. jets dropped their first bombs on the Islamic State in 2014, U.S. military leaders have called the air war in Iraq and Syria the most meticulous ever in avoiding unnecessary loss of life.

But the Pentagon has scrambled to address questions about the recent spike in civilian casualties.

That difficulty was apparent last month when, in the space of three days, senior military officials gave conflicting accounts about basic aspects of the air campaign.

First, a three-star general in Iraq said that there had been “relatively minor adjustments” to rules governing air operations against the Islamic State. The next day, his four-star boss told Congress there had been no change.

Amid the confusion, a spokesman for the U.S. military in Iraq and Syria weighed in the day after and tried to split the difference, telling reporters that while rules had “technically changed” last year, the moves “in no way reflect a lower tolerance for civilian casualties.”

These military officials were referring to changes made late last year, in the final weeks of the Obama administration, when lower-level officers in Iraq were granted power to approve strikes in certain situations. But even senior officers appear to disagree over whether that decision constituted a change in the rules of engagement.

Discussion of U.S. air tactics takes place as the new administration reviews the U.S. approach to the Middle East, including the larger conflict in Syria. Late last week, the Pentagon launched a missile attack on a Syrian military air base in retaliation for a chemical attack on Syrian civilians.

Since taking office, Trump has directed the military to accelerate the militants’ defeat and to examine whether regulations that exceed the requirements of international law should be lifted. The Trump White House also is re-examining restrictions the Obama administration put in place last summer as part of its effort to avoid civilian deaths. Those rules produced frustration among some military leaders, who complained of a slow operational tempo and missed opportunities against militants.

The stakes of those deliberations can be seen in Syria, where U.S.-backed forces are bearing down on Raqqa, the Islamic State stronghold. In Mosul, Islamic State fighters routinely fire from inhabited houses and appear to be positioning civilians to expose them to coalition strikes.

Military officials “may be struggling in part because the reality of the situation is that there will be a higher level of civilian casualties, and sometimes that really will be the outcome that military planners have to accept,” said Ryan Goodman, a professor at New York University Law School and a former Pentagon official. “But that’s very hard to explain to the public.”

Officials are also having trouble addressing the casualties because the military’s rules of engagement, known as ROE, are classified, meaning that military personnel can give only general assurance that no significant guidelines have changed.

But military experts point out that while the ROE, which guide when and how force may be used, are set by military leaders, they are subject to interpretation by personnel on the ground.

“The thing about the ROE is that they’re living documents,” said Jason Lyall, an associate professor at Yale who has studied military operations in Afghanistan. “They’re not just black and white.”

The confusion over the ROE is reminiscent of what took place in Afghanistan in 2010, when Gen. David Petraeus sought to counter confusion about whether he had altered an unpopular set of ROE or just standardized implementation of those rules across the battlefield.

Similarly, it has been challenging for the military to explain how last year’s decision to allow lower-level commanders to authorize strikes hasn’t made the air operations more risky for civilians.

That is in part because the process for approving strikes is so complex and varies depending on the type of target. A strike on a religious site, for instance, would require higher-level approval. Officials also have to factor in the target’s importance and location and whether a potential strike involves defense of American or allied forces.

It’s not clear whether the Trump administration will make adjustments to these rules. Defense Secretary Jim Mattis has already sent the White House a series of requests that would give military commanders increased decision-making power in conflicts in Yemen and other areas.

As more U.S. forces deploy closer to the front lines in Iraq, Syria and elsewhere, there is likely to be an increase in situations requiring strikes that would protect American troops.

That appears to have been the case in Yemen, where a Jan. 29 raid resulted in multiple civilians deaths after U.S. forces called for air support.

Ilan Goldenberg, a former Pentagon official who is now with the Center for a New American Security, said Trump’s own statements may influence how the fight is unfolding.

Signaling from a commander in chief “goes all the way up and down the system in small, subtle ways,” he said. “Generally, people are feeling the vibe that they should be a little more aggressive.”

Loveday Morris, Karen DeYoung, Thomas Gibbons-Neff and Greg Jaffe contributed to this report. Morris reported from Mosul.