WASHINGTON — Hate crimes against American Muslims have soared to their highest levels since the aftermath of the Sept. 11, 2001 attacks, according to data compiled by researchers, an increase apparently fueled by terrorist attacks in the United States and abroad and by divisive language on the campaign trail.
The trend has alarmed hate crime scholars and law-enforcement officials, who have documented hundreds of attacks — including arsons at mosques, assaults, shootings and threats of violence — since the beginning of 2015.
While the most current hate crime statistics from the F.B.I. are not expected until November, new data from researchers at California State University, San Bernardino, found that hate crimes against American Muslims were up 78 percent over the course of 2015. Attacks on those perceived as Arab rose even more sharply.
Police and news media reports in recent months have indicated a continued flow of attacks, often against victims wearing traditional Muslim garb or seen as Middle Eastern.
Some scholars believe that the violent backlash against American Muslims is driven not only by the string of terrorist attacks in Europe and the United States that began early last year, but also by the political vitriol from candidates like Donald J. Trump, who has called for a ban on immigration by Muslims and a national registry of Muslims in the United States.