In what is being described as a “national outbreak of hate,” the Southern Poverty Law Center (SPLC) said Tuesday that in the 10 days following the election of Donald Trump, there were 867 documented hate incidents, such as graffiti, verbal harassment, and in some cases physical violence.

The SPLC and a number of national rights groups that spoke to reporters Tuesday attribute the uptick in discriminatory harassment to the divisive rhetoric of the Trump campaign and a failure on the part of the president-elect to strongly condemn such actions.

“Mr. Trump claims he’s surprised his election has unleashed a barrage of hate across the country,” said SPLC president Richard Cohen. “But he shouldn’t be. It’s the predictable result of the campaign he waged. Rather than feign surprise, Mr. Trump should take responsibility for what’s occurring, forcefully reject hate and bigotry, reach out to the communities he’s injured, and follow his words with actions to heal the wounds his words have opened.”

Confirming an observed rise in harassment following the election, SPLC produced a report titled Ten Days After (pdf) that combines submissions to the group’s #ReportHate page with media accounts. Incidents were reported in every state with the exception of North Dakota, South Dakota, Hawaii, and Wyoming.

Wade Henderson, president of the Leadership Conference on Civil and Human Rights, said Trump needs to do more than tell his supporters to “Stop it,” as he did during his recent “60 Minutes” interview. Trump “needs to lead by example in both words and in deed,” Henderson said. “The nation—and the world—are watching.”

Sadly, according to the SPLC survey, children are perhaps most receptive to that messaging, with the bulk of the incidents reported in K-12 schools (183) and universities (140).

“This polarized and divisive election has left its mark on all of us, but most tragically on our children,” said Janet Murguia, president of the National Council of La Raza. “We have heard countless stories of harassment, intimidation, and bullying of Latino and other students in schools around this country. This cannot stand.”

“In a separate survey,” AP notes, “more than 10,000 teachers told SPLC they knew of more than 2,500 fights, threats and other incidents related to election rhetoric, and reported an increase in slurs and derogatory language, swastikas, Confederate flags, and Nazi salutes.”