Secretary of State John Kerry faced swift criticism Wednesday for suggesting the terror attack at Istanbul’s Ataturk Airport was evidence the Islamic State is getting “desperate” – an assessment one top Republican official said “defies reality.”

Kerry made the remarks late Tuesday at the Aspen Ideas Festival in Colorado, referring to ISIS by the name Daesh.

Crediting coalition efforts, Kerry said it’s been over a year since the group launched a “full-scale military offensive.”

"Now, yes, you can bomb an airport, you can blow yourself up. That's the tragedy. Daesh and others like it know that we have to get it right 24/7/365. They have to get it right for ten minutes or one hour. So it's a very different scale,” Kerry said. "And if you're desperate and if you know you’re losing, and you know you want to give up your life, then obviously you can do some harm.”

House Homeland Security Committee Chairman Mike McCaul, R-Texas, slammed the secretary’s assessment.

“They’ve said they’re on the run for many years, and they’re not,” McCaul told Fox News Wednesday morning. “I think the airstrikes have ramped up external operations … This is an unprecedented pace of terror in modern times. And so to say they’re on the run … absolutely defies reality.”

Underscoring Kerry’s questionable characterization was news Wednesday that Islamic State militants were pushing back U.S.-trained Syrian rebels in a battle for control of a town on the Iraqi border.

Also on Wednesday, President Obama spoke by phone with Turkish President Recep Tayyip Erdogan to express his condolences on behalf of the American people and to reaffirm the solidarity of the United States with Turkey following the terrorist attack, the White House said.

While no terror group has claimed responsibility for the Istanbul attack, Turkish officials told The Associated Press and Reuters that ISIS was the prime suspect. The attack killed at least 43 and injured hundreds, with the body county expected to keep rising. The attack at one of the world's busiest airports was committed by three suicide bombers who opened fire with AK-47s before blowing themselves up.

Former New York City Mayor Rudy Giuliani told Fox News these attacks – along with those in Paris, Brussels and, most recently, Orlando, Fla. – are “following their plan.”

“This isn’t accidental,” he said, adding “something’s wrong” with the secretary of state’s analysis.

Officials inside the Obama administration have given a conflicting picture of ISIS’ strength.

What’s clear is that the group is under pressure from coalition forces in its central territory of Iraq and Syria, even as it pushes back. The Iraqi government declared victory over the weekend in driving ISIS out of the Iraqi city of Fallujah, and the Pentagon confirmed that Iraqi security forces are in “100 percent control” of the city -- while also saying ISIS has not had a “strategic victory” in over a year.

The disconnect comes when administration officials discuss ISIS operations and strength outside Iraq and Syria.

Earlier this month, CIA Director John Brennan testified on Capitol Hill that despite progress against ISIS on the battlefield, “our efforts have not reduced the group's terrorism capability and global reach.”

He described the group as “resilient” and said they will wage their terror campaign globally in response.

“The group's foreign branches and global networks can help preserve its capacity for terrorism regardless of events in Iraq and Syria,” Brennan said. “In fact, as the pressure mounts on ISIL, we judge that it will intensify its global terror campaign to maintain its dominance of the global terrorism agenda.”

The chilling warning came after Obama said the anti-ISIS campaign “is firing on all cylinders” and the group “is under more pressure than ever before.”