Spain is the country, but Barcelona is in the region of Catalonia, which has a seriously radical leftist separatist movement going on. So I suspect that Spain got the warnings, informed the Mossos d’Esquadra (Catalan police force() - and the Mossos dropped it immediately because it came from Spain.
Heck, these terrorists had 100 propane tanks in their backyard,...and that didn’t bother the Mossos?
I read that the Catalonians were warned by the US via Madrid, but they are separatists and decided, “We don’t take orders from Madrid.” They have also invited Muslims to Catalonia for the past 30 years, assuming/ hoping that they would prefer to learn Catalan instead of Spanish. They haven’t. They didn’t. Now, in addition to stupidity, they have other problems compounded by stupidity. Of their own doing.