A request that white and non-black supporters limit their visibility at Canadian vigils for slain U.S. teen Michael Brown sparked a debate on social media, with some supporters accusing organizers of sending a pro-segregation message.

Vigils were held Tuesday evening outside the U.S. embassies in Toronto and Ottawa for those who wished to pay tribute to Brown, the unarmed black teen who was shot dead by a police officer in Ferguson, Mo., last summer.

A grand jury decided Monday not to indict Officer Darren Wilson in Brown’s shooting death, sparking angry protests and quiet vigils across the U.S. and in Canada.

The vigils in Toronto and Ottawa were organized via a Facebook forum called #BlackLivesMatter. On Tuesday, organizer Bilan Arte, deputy chair of the Canadian Federation of Students, posted a message with details about the Ottawa vigil, and included a note for “white and non black allies.”

While organizers “appreciate the solidarity” shown by non-black supporters, Arte wrote, they should keep in mind some instructions, including that they “refrain from taking up space in all ways possible.

“Remember that you are there in support of black folks, so should never be at the centre of anything.”

Arte also asked that they not speak to the media, and that they “stand behind black folks or between us and the police.

“If you see a cop harassing a black person, come in and engage. (Chances are they are least likely to arrest you.)”

Nearly 300 comments had been posted on Arte’s note by Wednesday morning.

The first commenter, Hamdi Loukoum, asked: “Wow, is this an anti-racist rally or a pro-segregation one?”

Loukoum’s comment received 24 “likes.”

Another commenter, Liam Noakes, said the vigil “should be looking to enhance different colours standing up and showing their support for blacks, which would mean speaking to the media and rallying in the same space as us.

“You want a change, you can't start excluding people just because they can't go through what we can. Gay rights activists who aren't gay make a huge difference, just like black rights activists who aren't black always will.”

Noakes’s comment received 48 “likes.”

Another commenter, Darian Parsons, asked if it wouldn’t help to “have support from the whole world, not just the black community...?”

Others accused those commenters of “making it all about you,” while some were concerned that white voices would overpower the feelings and opinions of black attendees.

“The problem with white people taking space is that they speak over us and it makes our voices go unheard,” a commenter named Jennifer posted. “It’s just as problematic when straight people speak over LGB+ people (sic).”

Her comment received 46 “likes.”

Another commenter, Nicole Desnoyers, rejected the suggestion that limiting participation of whites was segregationist.

“We need to stop equating centralizing black voices to segregation,” she wrote. “This ‘argument’ is used by white/non-black folks way too often and continuously derails conversations around fighting anti-black racism or doing anti-racism in a larger sense.”

Noakes later suggested that “excluding those who agree with us, doesn’t make us seem any less ignorant then (sic) the people who exclude us already.”

Jennifer then accused Noakes of “missing the point.

“We are not excluding anyone. No one is saying ‘no white people/non-black allowed.’ We are saying, don’t make it about you. Don’t speak for us. Support us without taking the spotlight off us.”