UPDATED 7/29 12:20 p.m. ET: Carlina Rivera, who represents the 2nd district of the NYC Council, confirmed overnight that Nikki has now been released. In a tweeted statement, she thanked advocates for their support and for bringing attention to this instance of "unidentifiable policing." She also called on NYC Mayor Bill de Blasio to address the arrest:

Prior to confirming the release, Rivera called the use of unmarked vans and plainclothes officers "in the middle of a peaceful protest" a "massive overstep." Legislation, she added, is being explored.

Bill de Blasio spoke on the incident in a daily briefing, saying the arrest was for damaging police property and that "it was the wrong time and the wrong place to effectuate that arrest."

See original story below.

On Tuesday afternoon a Black Lives Matter protester was grabbed by undercover NYPD cops and thrown into an unmarked van. The encounter, which reportedly occurred a little before 6 p.m. was captured on video by journalist Michelle Hooq and has since been circulating around social media. 

Police are alleging that the person thrown into the van was suspected of "damaging police cameras during five separate criminal incidents." 

The NYPD addressed the incident on social media, saying that the woman was arrested by Warrant Squad officers in Manhattans' Kips Bay neighborhood. They also said they used unmarked cars "to effectively locate wanted suspects." Police also reportedly used pepper spray on protesters. 

Gothamist reports that the person that was arrested is named Nicki and is an 18-year-old trans woman. 

"Four guys jumped out and a line of police bicycles came out from down the block — we hadn't seen them," a protester who witnessed the incident told Gothamist. "They pushed us back. They grabbed Nicki like she was a rag doll.... They had her arms on her neck and then they drove off." The 32-year-old man, who's name is Derrick, continued, "They're targeting our leaders... That's what's going to happen now."

People have taken to social media to blast the NYPD for the arrest. Many have compared what happened in NYC to Portland, Oregon, where unidentified federal agents arrested Black Lives Matter protesters and forced them into vans. 

Elected NY officials also commented on the arrest and called for an investigation.

Gothamist reports that the protesters eventually made their way to Madison Square Park and encountered police with riot shields who arrested some demonstrators.