Hundreds of anti-Israel protesters showed up to obstruct a Jewish reception at the world’s largest gay conference in Chicago on Friday.

The protesters chanted “From the river to the sea, Palestine will be free,” and held placards which read “Can’t Pinkwash away your guilt,” and “Pinkwashing isn’t pretty.”

“Pinkwashing” is a term coined to suggest that Israel pushes its gay rights agenda as a way of obfuscating its treatment of Palestinians.

In addition to blocking people from attending the reception, the protesters managed to storm the conference hall and overtake the stage, preventing the American Jewish and Israeli delegates from speaking.

The Friday reception, which was scheduled to follow Jewish prayers, was hosted by A Wider Bridge, an organization that builds connections between LGBTQ communities in North America and Israel. The organization’s executive director, Arthur Slepian, released a statement:

“In the hallway outside our program, about 200 protesters blocked many others from entering the room, and turned the LGBT Task Force’s conference and the Hilton Hotel into a fire storm of hate that felt truly unsafe and threatening to many of our participants, and especially to our Israeli guests,” he said.

He added that the protesters denied the Jerusalem speakers their humanity and silenced their voices, and castigated the conference organizers for doing “tragically little” to provide for the speakers’ safety and security.

The National LGBTQ Task Force, the U.S.’s oldest gay rights advocacy group and the organizers of the annual Creating Change conference, announced that it was cancelling the Jewish reception.  The announcement was made amid protests from gay anti-Israel activists who called Israel a “settler colonial nation engaged in apartheid.”

Two days after the announcement, the organizers revoked their decision following counter-protests from A Wider Bridge and others.

“In reversing the decision today, we want to make it quite clear that the Creating Change Conference will always be a safe space for inclusion and dialogue for people with often widely different views,” said the organization’s executive director, Rea Carey, in a statement.

Carey also expressed her concern over “the intense escalation that has occurred over the last couple of days and the threats towards people who hold a range of views” and urged all who were planning to protest the reception to remain “peaceful.”