Foreign fighters from around the globe continue to pour into Iraq and Syria to join up with the self-proclaimed Islamic State—despite ISIS’s loss of two major cities, four U.S. and military officials told The Daily Beast.

In fact, there is some evidence that the number of fighters from Europe has increased in the last six months, one U.S. official said, from a total of 5,000 fighters six months ago to roughly 8,000 now. In other words, there’s been a 60 percent increase in these recruits in just half a year.

Either way, two military officials said, there is no evidence of any change in the foreign fighter flow since ISIS last major battlefield setback, in Saddam Hussein’s hometown of Tikrit.

“The recruitment channels continue unabated,” the U.S. official explained.

The continued flow punctures a key component of the U.S.-led coalition’s strategy: that military losses, coupled with coalition air superiority, could shift the momentum against ISIS’ favor.

ISIS’s vision of a caliphate could not exist without landmass, the U.S. military has repeatedly said. And ISIS has depended on new cities to plunder their banks of money and their citizens with taxes.

“The narrative depends on them being able to hold the territory,” one defense official explained.

Earlier this month, the U.S. military distributed a map boasting ISIS’s territorial losses in Iraq, saying the U.S.-led air campaign and Iraqi ground forces had reclaimed 25 percent of area once under ISIS control.

But the problem is that while ISIS needs landmasses, some areas are more valuable than others, the military official said. And the two major cities that ISIS was not able to keep or win over—the Syrian city of Kobani and Tikrit—were not that strategically important to ISIS, the U.S. officials said.

“We have exaggerated and overhyped these tactical advancements in areas north of Baghdad as well as Kobani,” an adviser to the U.S. government effort in Iraq told The Daily Beast.

The capital of its caliphate in Iraq is that country’s second-largest city, Mosul, and that remains under ISIS control. ISIS also holds sway over much of Iraq’s restive Anbar province and controls the central Iraqi city of Baiji, as Iraqi forces fight to hold onto the refinery there. In Syria, there is little evidence of any major losses of territory there—although competing jihadist groups like Jabhat al-Nusra have been taking towns from the Syrian government. The city of Raqqa remains under ISIS control.

“They still hold the core territory,” said Christopher Harmer, a senior naval analyst with the Middle East Security Project for the Washington, D.C.-based Institute for the Study of War. “That ISIS heartland still seems pretty secure.”

Moreover, because Syrian President Bashar al Assad’s hold on the country there appears increasingly fragile, more fighters are traveling to Syria in hopes of tipping the battle to their advantage. And on social media, the group has successfully spun the losses as wins.

ISIS hoped to win over the northern Syrian city of Kobani. But that was aspirational, not key to any access points to other cities or financing, U.S. military officials conceded. After months of fighting between ISIS fighters and Kurdish peshmerga forces, bolstered by an aggressive U.S.-led air campaign, ISIS forces began withdrawing in February.

The U.S.-led coalition has conducted nearly daily strikes on Kobani since then, in a push to ensure ISIS does not return and help peshmerga forces expand the area they control around the city.

ISIS was entrenched in the central Iraqi city of Tikrit for roughly eight months leading up to the fight there. Tikrit, while symbolically important, also exposed the massive amount of military force needed to take it out of ISIS’s grip. The Iraqi security forces leaned on Shiite-dominated militias and Iranian advisers and weapons in the early weeks in the battle for Tikrit. And when that floundered, the U.S.-led coalition began an air bombardment campaign; the city fell a week later. To win the city, the Shiite militias sustained heavy losses, and the Iraqi military outsourced its military plans.

“Tactically, ISIS lost Tikrit. Strategically, it wasn’t that big of a loss. They bled the Shiite militia. And they established the standard. It took air superiority and all these Iranians military advisers,” Harmer said.

Many hoped the fall of Tikrit would shift the momentum away from ISIS. Days after the city fell, Iraqi and U.S. officials debated which ISIS-controlled city to strike next; the Iraqi government’s push to tackle Anbar next prevailed. But so far, there is no evidence of a major Anbar campaign but rather sporadic fight for control of the province’s capital, Ramadi. According to one U.S. official, the Anbar campaign has not begun, in part, because of infighting within the Iraqi government.

On the ground in places like Ramadi, local officials said the majority of those killed in battle on the ISIS side are Iraqi, suggesting that foreign fighters are not on the front lines but rather in a support role.

On social media, ISIS has called both Tikrit and Kobani victories. They claim the Tikrit campaign only exposed how weak the Iraqi security forces are. And they note that Kobani was all but destroyed to keep it out of ISIS hands.

Observers said that while the reason foreign fighters are joining ISIS is varied, not all are moved by territorial wins and losses, but rather the hopes of living amongst a caliphate. And while military losses can have an effect that without an equally aggressive push on their finances, the territorial gains can only have so much of an effect.

Kobani and “Tikrit do not make or break ISIS,” the adviser explained.

Perhaps most importantly, they note that there appears to be a ground shift in Syria, amid reports that Assad can no longer recruit the number of troops he needs to hold ground.

“ISIS says the overall effort is winning. They are wearing down the Assad regime,” the adviser explained. “Success breed recruitment.”