Transcript for US authorities warn about possible homegrown attack with acid
Now, a frightening attack near a London shopping center. Some kind of substance, possibly acid, injuring a half dozen people. Raising concerns. Erielle reshef is here in the studio. Reporter: Good morning. The department of homeland security is warning those attacks are simple to carry out with house hold products you may have in your own cabinet. This could be an enticing tactic for terrorists to use right here at home. This morning, an urgent and ominous warning from U.S. Law enforcement on the heels of two terrifying attacks in Europe. Terrorists could be planninging to carry out chemical spray ands a -- acid assaults here at home. Home grown violent extremists could find the appealing. The idea we could have attacks like those here is just -- really quite possible. Reporter: In least London, Saturday, a fight between two groups led to six people doused with a noxious substance. A teen anger arrested. I think it's scary, disgusting, horrible that people can't just walk and be safe anymore. Reporter: That scene playing out less than a week after four American college student were sprayed with hydro coloric acid outside Marseilles, France. These atracks hard to prevent. Reporte . The short answer is, they're easy to carry out. You can't stop them unless you know about it in sad Vance. Reporter: The number of acid attacks has increased in Britain over the years. Mostly related to robberies and gang-related violence. Officials are saying ISIS are using lower-tech methods. Hard to protect against. Thank you. Appreciate it. Unpleasant to say the least. Back to rob in Atlanta, on
This transcript has been automatically generated and may not be 100% accurate.