A dozen film-makers and artists have withdrawn their work from the world’s largest documentary festival after its organisers strongly condemned the use of the slogan “From the river to the sea, Palestine will be free” at an opening-night protest.

During a speech by the artistic director of the International Documentary Festival Amsterdam (IDFA), Orwa Nyrabia, at the start of the event last Thursday, three activists took to the stage holding a sign with the slogan, which some say is a call for a secular state in historic Palestine but which others note is used by radical Islamist groups to promote the eradication of Israel.

Nyrabia reportedly joined sections of the audience in applauding the intervention, but later said he could not see the words on the banner from where he sat on stage. “I clapped to welcome freedom of speech and not to welcome the slogan,” he said, adding that the slogan was “a triggering statement and an offensive declaration for many, regardless of who carries it”.

The organisers of the IDFA, which runs until 19 November, said the use of the words went against their aim to provide a safe space for civic debate. “There are many ways that people use or read this slogan, and that various sides use it in opposing ways, all of which we do not agree with, and we believe that this slogan should not be used in any way and by anybody any more”, the IDFA said.

Before the film festival issued its statement, 16 leading figures from the Israeli film industry signed an open letter expressing their “uttermost dismay, disappointment and concern” at the opening-night protest and reports of its positive reception.

The IDFA’s statement on “from the river to the sea” in turn prompted protests from the Palestine Film Institute (PFI), a national body responsible for promoting the cinema of Palestine that is usually hosted by the festival for one day each year.

As of Tuesday morning, 12 out of the 300 film-makers attending the festival had followed the PFI’s call to withdraw their films, including Basma al-Sharif, a juror of the festival’s experimental “Envision” competition.

Sharif, whose parents were born in Palestine, said “from the river to the sea” was an anti-apartheid slogan advocating a state in which people of all faiths had equal rights, and that, by denouncing it, the IDFA had aligned itself with the Israeli government’s “aggressive propaganda”.

The slogan, a reference to the land between the Jordan River, which borders eastern Israel, and the Mediterranean Sea to the west, is also used in the 2017 constitution of Hamas, the Islamist militant group whose gunmen killed 1,200 people in its attack on 7 October.

Germany, which last week announced a complete ban on Hamas’s activities, now lists “from the river to the sea” as one of the marks of the radical Islamist group, meaning its use in public could count as a criminal offence similar to publicly displaying a swastika.

In the Netherlands, however, where the IDFA festival is taking place, the court of appeal last month upheld a previous ruling that the slogan deserved legal protection on free speech grounds.

Not all Palestinian film-makers have withdrawn their work from the festival. Mohamed Jabaly’s Life is Beautiful, which deals with the young Palestinian film-maker’s own statelessness, will continue to be shown.

“I want to be heard,” Jabaly told the Guardian. “Because now that everything has been destroyed, what is left are our stories and freedom of expression.”