In our ongoing series, Issues That Matter, we are taking a closer look at the United States' fight against the Islamic State of Iraq and Syria (ISIS).

The State Department says ISIS has lost about 78 percent of its territory in Iraq and 58 percent in Syria since its peak in 2014. Nearly a third of those losses have happened in the past six months.

Brett McGurk CBS News

Brett McGurk, special presidential envoy for the Global Coalition to Counter ISIS who recently returned from a 12-day trip to the Middle East, said ISIS forces in Raqqa, Syria, are "fighting for their life, block-by-block."

The United Nations is calling for a humanitarian pause to the fighting with ISIS in Raqqa, however, so civilians can evacuate. U.S.-backed forces began an offensive against the city, ISIS's self-declared capital, in June, and the U.N. estimates 20,000 people are trapped and at risk. McGurk said it's an "extremely, extremely difficult" situation, and the U.S. in "mindful" of the report.

"All these people in Raqqa who are fleeing ISIS, they're fleeing into the lines of the force we're working with, and we are now working with the United Nations to try to take care of them. … What they tell us is that the number one thing that we have to do to help these people is defeat ISIS. ISIS is using civilians as human shields, they're using a children's hospital in Raqqa as their primary base of operations," McGurk said. "So the number one thing we have to do is defeat them and defeat them as soon as we can. And it's going well."

McGurk said President Trump has "focused like a laser destroying ISIS."

"So that meant let's look at what is working, and try to reinforce those efforts, and let's look at things that haven't worked and try to improve them," McGurk said. "One thing he did very early on was delegate authorities down to the lowest level in the field. What that means in practice is that as our military experts see an opportunity, they can seize it."

He said the shortened decision-making cycle makes a difference in the field.

But the war against ISIS is not contained within the borderlines of Syria and Iraq. In the latest string of vehicle attacks, ISIS claimed responsibility for the terror attacks in Barcelona and Cambrils in Spain last week that left 15 people dead.

McGurk said the key to stopping these types of attacks is information sharing.

"We have to shrink their territory. At the same time, through a global coalition, we built a global coalition of 69 countries, and working to share information as we collect data off the battlefield of who these people are, we're putting them into a global database," McGurk said.

He said the overall effort to fight ISIS will shift from the "military phase in Iraq and Syria to law enforcement, intelligence and sharing information."

"One of the newest members of our coalition is actually Interpol because we're building a global database. We have 19,000 names now of known terrorists who either joined ISIS or tried to join ISIS, trying to move into Iraq and Syria, and we want to make sure that every law enforcement agency, every border patrol officer can check a database and stop these people in routine traffic stops, as they're trying to cross borders," McGurk said. "This is the long-term effort, the long-term fight in information sharing, trying to close a net globally to make sure these people can't travel. And we're just as focused on that as we are on the military side in Iraq and Syria."

ISIS also recently released a propaganda video that claims to show a 10-year-old American boy.

U.S. officials tell CBS News that clues in the video seem to indicate the boy is an American, but the details of his identity and how he ended up with ISIS are not clear.

The boy makes threats against the U.S. that appear to be scripted.

"I can't confirm this video or who this child is," McGurk said. "They use children as human shields. They try to recruit children as suicide bombers. They have used children inside Iraq to blow up children's soccer games, to attack ice cream parlors of families going to get – celebrate the Eid [holiday]. That's what this organization is, and that's why the sooner it can be defeated, the better. So we are moving as fast as we possibly can, mindful of how difficult this is."