Anti-Semitic incidents in the United States rose by more than one-third in 2016 and shot up 86 percent in the first three months of 2017, the Anti-Defamation League reported.

There has been a massive increase in harassment of American Jews, largely since November, and at least 34 incidents linked to the presidential election that month, the ADL reported Monday in its annual Audit of Anti-Semitic incidents.

There were a total of 1,266 acts targeting Jews and Jewish institutions during 2016, a 34 percent increase of incidents of assaults, vandalism, and harassment over the previous year. Nearly 30 percent of those incidents, or 369 of them, occurred in November and December.

The acts included 720 harassment and threat incidents, an increase of 41 percent over 2015; 510 vandalism incidents, an increase of 35 percent; and 36 physical assault incidents, a decrease of 35 percent.

There are preliminary reports of 541 anti-Semitic incidents for the first quarter of 2017.  One reason for this jump in number of incidents appears to be the bomb threats called into Jewish community centers and other Jewish institutions around the country. Most of these were made by an Israeli-American teen who was arrested in Israel and charged in the United States.

The 541 anti-Semitic incidents so far in 2017 include: 380 harassment incidents, including 161 bomb threats, an increase of 127 percent over the same quarter in 2016; 155 vandalism incidents, including three cemetery desecrations, an increase of 36 percent; and six physical assault incidents, a decrease of 40 percent.

“There’s been a significant, sustained increase in anti-Semitic activity since the start of 2016 and what’s most concerning is the fact that the numbers have accelerated over the past five months,” ADL CEO Jonathan A. Greenblatt said in a statement. “Clearly, we have work to do and need to bring more urgency to the fight. At ADL, we will use every resource available to put a stop to anti-Semitism. But we also need more leaders to speak out against this cancer of hate and more action at all levels to counter anti-Semitism.”

Despite the fact that recent high-profile incidents in Missouri have contributed to those numbers and raised the level of concern in the state, ADL regional director Karen Aroesty does not think Missouri has a unique problem with anti-Semitism. In February, vandals knocked over 154 headstones at Chesed Shel Emeth Cemetery in University City — though the incident has not been declared a hate crime and no arrests have been made. In March, the FBI arrested Juan Thompson, a St. Louis resident suspected of making bomb threats against eight Jewish community centers around the country.

“I think we are experiencing the same kind of spike that is happening around the country,” said Aroesty, whose ADL office covers Missouri and southern Illinois. 

The states with the highest number of incidents were those with large Jewish populations, including California, New York, New Jersey, Florida and Massachusetts.

While incidents on college campuses stayed mostly static, after nearly doubling in 2015, incidents in non-Jewish elementary, middle and high schools increased 106 percent from 114 in 2015 to 235 in 2016. Another 95 of these incidents were reported for the beginning of 2017.

Aroesty said one of her biggest concerns is the increase in school-based incidents, particularly anti-Semitic online activity. For example, in December, Clayton High School administrators disciplined students who allegedly used a closed Instagram group to post anti-Semitic images and language about fellow students.

The ADL has been tracking anti-Semitic incidents since 1979.  During the past decade, the number of reported anti-Semitic incidents peaked at 1,554 in 2006.

Separately, Tel Aviv University’s watchdog on anti-Semitism reported Sunday that the number of anti-Semitic incidents worldwide has decreased by 12 percent in 2016 despite a spike in cases in the United Kingdom and the United States.