A senior U.S. intelligence officer likened the Belgian security forces to “children.”

“It’s really shitty tradecraft,” the agent told The Daily Beast.

Brussels has become a hotbed of terrorism—concentrated in  the Molenbeek district near the city center—and yet the Belgians have made little progress in disrupting a network of violent extremists linked to last year’s Paris attacks that killed 130 people.

Even before the arrest last week in Brussels of Salah Abdeslam, a suspected terrorist behind the Paris attack, there were worries among many U.S. counter terrorism officials of an attack in Belgium. The Belgian authorities had long struggled to resource a counter terrorism campaign. At the same time, it ostracized its burgeoning minority communities, creating isolated enclaves like Molenbeek where potential jihadists could easily hide.

After Abdeslam's arrest, many in Belgium feared a retaliatory attack. But while U.S. officials sought to help as part of a growing push for U.S. and European cooperation, there were limits, given Belgium’s limited security resources and amid a growing migration community from places like Syria.

News of today’s attack was met in some parts of Washington with resigned frustration.

“There was only so much we could do to help,” one official explained to the Daily Beast.

“Belgium has been stepping up the amount of people they’re devoting to intelligence and law enforcement but they’re playing catch-up and we’re seeing the terrible results of that today,” Rep. Adam Schiff, the senior Democrat on the House Permanent Select Committee on Intelligence, said on MSNBC.

Indeed, an official said there were warnings as recent as this weekend.

A frustrated U.S. intelligence official bemoaned the state of the counterterrorism apparatus in Belgium and across Europe.

“Even with the EU in general, there’s an infiltration of jihadists that’s been happening for two decades. And now they’re just starting to work on this. When we have to contact these people or send our guys over to talk to them, we’re essentially talking with people who are—I’m just going to put it bluntly—children. These are not pro-active, they’re don’t know what’s going on. They’re in such denial. It’s such a frightening thing to admit their country is being taken over.”

Belgium is further handicapped by the fact that it is believed more than 500 jihadists have returned from the fight in Syria and have either been radicalized by Islamic State or given specific tasks by the terror group. Authorities know pretty much who they all are, but as the article notes, they are short of people to keep track of them. It takes about 100 security personnel to keep constant surveillance on one terrorist. Few nations in Europe have the resources to accomplish that goal.

In America, we are in a little better shape because our problem with jihadists numbers in the dozens rather than the hundreds. But as the Boston Marathon bombing showed. even suspected terrorists can fall through the cracks. Of far more concern are American born Muslims who have been radicalized here. They tend not to appear on anyone's radar until they carry out an attack.

Europe is playing catch up in their counterterrorism efforts. It is a virtual certainty until they can devote the resources necessary to protect their citizens, more such attacks will occur.