The White House suggested Friday that more terrorist attacks are happening in Europe and elsewhere because of the progress the U.S.-led coalition is making on the battlefield against the Islamic State in Iraq and Syria.

Discussing the recent spate of Islamic State-related or inspired terrorist attacks around the world, the president's top spokesman said the U.S. has been focused on countering these types of "lone-wolf" attacks "all along and we've made some progress."

"But it's more of a significant threat now, according to some analysts, because of the important progress that we've made in undercutting the fantasy of [an Islamic State] establishing a caliphate in Iraq and Syria," Josh Earnest told reporters.

Asked if the White House, not just outside analysts, agrees with this theory, Earnest said: "This is something we're watching closely and we want to be mindful of this potential risk."

Since Islamic State began a murderous march across Iraq in the summer of 2014, the U.S. and its anti-Islamic State coalition partners have been focused on trying to stop the group's ability to launch large-scale, 9/11-type attacks from inside Iraq and Syria.

"That ability has been degraded," Earnest said, noting that many Islamic State leaders are "quite concerned about their own security" in recent weeks.

He also cited progress in stopping terrorist crossings across the border between Syria and Turkey and "great strides" in shutting down Islamic State's financing system with the sale of oil on the black market and hostage taking, although he said "there is more that we need to do" on both those scores.

In addition, Earnest said Islamic State leaders in recent months have stopped encouraging recruits to come to Syria and join the fight and instead have encouraged them to go to Libya and "pick up" the fight there or "go to your home country and launch attacks from there."