A controversial American author and blogger who slams Islam drew more than 200 people to a Calgary speech Thursday evening along with a cross-section of critics who say he incites hate towards Muslims.

Robert Spencer is the author of several books on Islam including some best sellers, but his words prompted a ban from the United Kingdom in 2013 and some in local faith communities condemn Spencer's sweeping statements on Islam.

"We're not trying to prohibit him from speaking," said Rabbi Shaul Osadchey of the Beth Tzedec Congregation in Calgary.

"Our concern is that this kind of speech then puts in people's minds different perceptions about the community and I don't … I know that the Jewish community does not support his point of view in the main. There are obviously some people that find him to be credible, but by and large he's been discredited by human rights and civil rights organizations throughout North American, prominently the Anti-Defamation League and the Southern Poverty Law Centre in the States."

The group sponsoring Thursday's event is the Jewish Defence League of Calgary. Members of the Jewish Defence League were branded extremists engaged in planning "terrorist plots" in 2001 by the FBI.

Robert Spencer speaks in Calgary

The group sponsoring Thursday’s event is the Jewish Defence League of Calgary. (Allison Dempster/CBC)

Imam Syed Soharwardy — president of the Islamic Supreme Council of Canada and a prominent critic of terrorist acts — says Spencer is a dangerous speaker.

"Robert Spencer incites hate. So, that's the problem," Soharwardy said.

"When he comes to this country and incites hatred in the minds and the hearts of people and he creates misunderstandings, that definitely is a very dangerous person."

A multi-faith coalition representing Christians, Jews and Muslims issued a joint statement in advance of Spencer's event calling on Calgarians to reject his message and instead "pursue the path of religious literacy and to support efforts to build bridges of respect and understanding."

For his part, Spencer deflects criticism by saying others want to silence him.

"It's a well-worn tactic of groups that for some reason are arrayed against opponents of jihad terror, that they charge them with racism, with bigotry, with hatred and so on for telling truths that they don't want known."

Robert Spencer

More than 200 people wanted to hear what controversial author/blogger Robert Spencer had to say in Calgary Thursday. (Allison Dempster/CBC)

But to Rabbi Shaul Osadchey, Spencer's words are designed to divide, not unite.

"We're expending a lot of energy and effort to create harmony and build good interfaith relationships between Christian, Jewish and Muslim communities and somebody comes in with a speech that is offensive, that misconstrues and stereotypes any one of us," Osadchey said.

"It just undermines our efforts here in the community."

With files from Allison Dempster