Hyper-liberal Oscar-winning documentary filmmaker Michael Moore challenged Republican presidential frontrunner Donald Trump by holding a sign reading “We Are All Muslim” outside Trump Tower on Wednesday before penning an open letter to the candidate on Facebook.

In his letter, Moore, who recently offered his Michigan apartment to Syrian refugees before inviting his fans to open their own homes, claimed he and Trump met on a talk show in 1998 and the billionaire businessman had asked him not to “go after” him.

“I thought, what are we, in 3rd grade?” Moore wrote. “I was struck by how you, a self-described tough guy from Queens, seemed like such a fraidey-cat. You and I went on to do the show. Nothing untoward happened between us. I didn’t pull on your hair, didn’t put gum on your seat. ‘What a wuss,’ was all I remember thinking as I left the set.”

Moore added that Trump is now similarly afraid of Muslims, after proposing a temporary ban on all Muslim immigration to America “until our country’s representatives can figure out what is going on.”

Moore wrote:

And now, here we are in 2015 and, like many other angry white guys, you are frightened by a bogeyman who is out to get you. That bogeyman, in your mind, are all Muslims. Not just the ones who have killed, but ALL MUSLIMS. Fortunately, Donald, you and your supporters no longer look like what America actually is today. We are not a country of angry white guys. Here’s a statistic that is going to make your hair spin: Eighty-one percent of the electorate who will pick the president next year are either female, people of color, or young people between the ages of 18 and 35. In other words, not you. And not the people who want you leading their country.

The filmmaker then asked Trump to “leave the rest of us alone so we can elect a real president who is both compassionate and strong.”

“We are all Muslim. Deal with it,” Moore concluded.

Moore has become increasingly vocal about his dislike for the Republican frontrunner; last week, he invited Facebook followers to report Trump for “hate speech” in an effort to have him banned from the social media service.

In an interview with the Daily Beast the day before his latest stunt, Moore said Trump should embrace his “female side.”

“All men have estrogen in them. We all have a bit of estrogen in us. Sometimes, I’ve noticed in our gender the guys who have to do a lot of huffing and puffing, they may be better embracing the female side of themselves,” Moore told the outlet. “They may be a little happier. He might be one of those people.”

Read Moore’s full letter to Trump here.