This week marked a turning part in the Black Lives Matter movement. Since bursting onto the national scene after the shooting death of Mike Brown, an unarmed 18-year-old in Ferguson, Missouri, last year, the movement's leaders have called for a systemic overhaul of America's criminal justice system. They have also emphatically encouraged using the phrase Black Lives Matter, and no variations. The rationale: Yes, all lives matter, but black lives are under siege, and specifying their importance doesn't erase that of any others.

This week, however, a twist on that phrase lit up social media, in the form of #BlackTransLivesMatter, with the full support of the movement's organizers and cofounders. On Tuesday, a national day of action took place in more than 20 cities across the country calling for an end to the record number of black transgender women who've been killed in recent years. In the past two years alone, more than 25 trans women of color have been killed, and one of the leading causes of their deaths is intimate partner violence.

For organizers, it was important to put the movement's spotlight on "trans community that's historically been erased," Elle Hearns, a longtime #BlackLivesMatter organizer who is also a transgender black woman, told Mic.

For the black transgender women who have long been a vital part of the movement, this week's call to action was a chance to ask their cisgender allies for examples of true solidarity.

"We wanted to show that it's not just trans women are outraged, and that cisgender people confront the ways that they're complicit in transphobia," Hearns says. "We wanted folks to really commit to what they were gonna do following the action."

This is what that solidarity looks like:

An epidemic of violence. This week, Keyshia Blige, a 33-year-old in Aurora, Illinois, became the 19th reported black transgender woman to be killed so far this year. Though she was killed in March, she was was only identified publicly this week. Her death spurred yet another call to action by black trans women and their allies to interrupt a deadly culture of violence that they say starts with refusing to acknowledge these women's lives.

"The goal really was to see what kind of commitment folks were making," Hearns said of this week's actions. "We need people to commit to something beyond this moment."