Attacks perpetrated by lone actors are the biggest terrorism threat to July 4th festivities in New York City and elsewhere, federal authorities said in a threat assessment obtained by CNN.

Watching community fireworks shows or gathering for concerts and barbecues this Fourth of July holiday will come with an increased security risk. The DHS and FBI issued warnings ahead of the patriotic holiday weekend, warning of lone wolf attacks on large gatherings in major U.S. cities like New York.