Donald Trump’s rhetoric has encouraged acts of terror in his own country, the head of a leading American Jewish organisation has said.

He also raised fears about elements of the UK’s Brexit campaign, saying: “We are concerned about the rise of populism. Donald Trump’s victory, the Brexit vote, the election victories of far-right politicians in different parts of Europe: these things are concerning.

“Often – and I’m understating here – these populist movements do not turn out very well for minorities, particularly for Jewish minorities.”

“We all need to be watching very carefully to make sure things move in a direction that acknowledges that inclusivity and immigration and pluralism contribute not only to the dynamism of our economies, but also to the health of our societies and the richness of our democracies.”

Mr Greenblatt, whose organisation combats hate crime and anti-Semitism, criticised Mr Trump for both his campaign rhetoric and his slowness to condemn about 140 bomb threats to US Jewish institutions that have occurred since January, the month the 45th President took office.

These, he said, had gone way beyond threats to the ADL’s offices in Atlanta, Boston, Washington and New York, with evacuations of schools and homes for older people leading to “threatened pre-school children being hustled out of classrooms, elderly patients being wheeled out of their care programmes”.

Other minorities had been similarly affected, said Mr Greenblatt, with some suffering fatalities. Two weeks ago, in Kansas, Srinivas Kuchibhotla, an Indian immigrant was shot dead after allegedly having been mistaken for an Iranian.

In January, just hours after Mr Trump announced a “travel ban” against citizens from seven majority-Muslim countries, a Texas mosque was burned down.

“These criminal acts are designed to terrorise the community,” said Mr Greenblatt. “Let’s be clear, they are terror.”

“In our current environment,” he added, “The extremists feel emboldened.”

Mr Greenblatt, a former aide to Barack Obama, said this was partly due to social media providing extremists with an easy way to contact like-minded individuals under the cover of anonymity where before they were “hiding behind their white hoods, in cornfields, under the cover of night”.

But a second “big factor”, he said, was a kind of political rhetoric that has “moved from the margins right into the mainstream”.

Referencing some of the more incendiary statements from Mr Trump’s or members of his administration, Mr Greenblatt said: “Words have consequences.

“When you describe the Mexicans coming across the border as murderers and rapists, you should not be surprised when it kicks up an anti-immigrant fervour.

“When you describe Islam as more of a [political] ideology [than a religion], you should not be surprised if anti-Muslim sentiment is kicked up around the country.

Donald Trump's most controversial quotes Show all 14 1 /14 Donald Trump's most controversial quotes Donald Trump's most controversial quotes On Isis: "Some of the candidates, they went in and didn’t know the air conditioner didn’t work and sweated like dogs, and they didn’t know the room was too big because they didn’t have anybody there. How are they going to beat ISIS?" Getty Donald Trump's most controversial quotes On immigration: "I will build a great wall — and nobody builds walls better than me, believe me —and I’ll build them very inexpensively. I will build a great, great wall on our southern border, and I will make Mexico pay for that wall. Mark my words." Reuters Donald Trump's most controversial quotes On Free Trade: "Free trade is terrible. Free trade can be wonderful if you have smart people. But we have stupid people." PAUL J. RICHARDS | AFP | Getty Images Donald Trump's most controversial quotes On Mexicans: "When Mexico sends its people, they’re not sending their best. They’re sending people that have lots of problems. They’re bringing drugs. They’re bringing crime. They’re rapists." Getty Donald Trump's most controversial quotes On China: "I just sold an apartment for $15 million to somebody from China. Am I supposed to dislike them?... I love China. The biggest bank in the world is from China. You know where their United States headquarters is located? In this building, in Trump Tower." Getty Images Donald Trump's most controversial quotes On work: "If you're interested in 'balancing' work and pleasure, stop trying to balance them. Instead make your work more pleasurable." AP Donald Trump's most controversial quotes On success: "What separates the winners from the losers is how a person reacts to each new twist of fate." Donald Trump's most controversial quotes On life: "Everything in life is luck." AFP Donald Trump's most controversial quotes On ambition: "You have to think anyway, so why not think big?" Getty Images Donald Trump's most controversial quotes On his opponents: "Bush is totally in favour of Common Core. I don't see how he can possibly get the nomination. He's weak on immigration. He's in favour of Common Core. How the hell can you vote for this guy? You just can't do it." Reuters Donald Trump's most controversial quotes On Obamacare: "You have to be hit by a tractor, literally, a tractor, to use it, because the deductibles are so high. It's virtually useless. And remember the $5 billion web site?... I have so many web sites, I have them all over the place. I hire people, they do a web site. It costs me $3." Getty Images Donald Trump's most controversial quotes On Barack Obama: "Obama is going to be out playing golf. He might be on one of my courses. I would invite him. I have the best courses in the world. I have one right next to the White House." PA Donald Trump's most controversial quotes On himself: "Love him or hate him, Trump is a man who is certain about what he wants and sets out to get it, no holds barred. Women find his power almost as much of a turn-on as his money." Getty Images Donald Trump's most controversial quotes On America: "The American Dream is dead. But if I get elected president I will bring it back bigger and better and stronger than ever before and we will make America great again." GETTY

Mr Greenblatt added: “A lack of words has consequences. When you soft-pedal on anti-Semitism and fail to call it out, you should not be surprised if extremists feel the wind at their backs.

“By not speaking out against this firmly and forcefully, by not rejecting it with the same kind of energy he has brought to criticising Broadway plays or comedy shows – that is certainly part of the reason why we are in this situation.”

Mr Greenblatt also described the way Mr Trump accused a Jewish reporter of lying and ordered him to sit down after being asked a question about rising anti-Semitism, as “a terrible moment, a moment where we saw the alt-right rejoicing, because it was a realisation of their hopes”.

But, like Jake Turx, the reporter who asked the question, Mr Greenblatt stressed that he did not believe Mr Trump was himself anti-Semitic in any way.

Rather, said Mr Greenblatt, Mr Trump was a man whose own daughter Ivanka was Jewish, having converted to marry Jared Kushner, an Orthodox Jew. Mr Trump was, therefore, the first US president to have Jewish children and grandchildren.

“This man has a closer relationship to the Jewish people than any president in US history. At the same time, his lack of calling out [anti-Semitism] firmly has in part contributed to this environment. It is perplexing.”

Mr Greenblatt said, however, that he had been encouraged by recent signs that the Trump administration was finally starting to speak out clearly against anti-Semitism.

He was, he said, greatly encouraged by Mr Trump beginning his first speech to Congress by saying that threats against the Jewish community and the Kansas shooting “remind us that we are a country that stands united in condemning hatred in all its forms”.

Mr Greenblatt also praised Vice President Mike Pence for joining a community clean-up of a vandalised Jewish cemetery outside St Louis, Missouri.

Mr Greenblatt said: “We wish it had been sooner, but it is important. The administration is starting to send the right messages, which is great and important.”

Calling on Mr Trump to convene a task force to come up with a strategy for addressing anti-Semitism and other forms of race hatred, Mr Greenblatt added: “What is critical is to follow up words with action, with a policy plan to really address anti-Semitism.