More than 380 figures from the cinema world including "Schindler's List" actor Ralph Fiennes condemned "genocide" in Gaza in an open letter published on Tuesday ahead of the Cannes Festival opening.
"We cannot remain silent while genocide is taking place in Gaza," read the letter initiated by several pro-Palestinian activist groups and published in French newspaper Liberation and US magazine Variety.
The signatories -- which include Hollywood stars Richard Gere and Susan Sarandon, as well as acclaimed Spanish director Pedro Almodovar and former Cannes winner Ruben Ostlund -- decried the death of Gazan photojournalist Fatima Hassouna.
Hassouna, 25, is the subject of a documentary which will premiere in Cannes on Thursday by Iranian director Sepideh Farsi, titled "Put Your Soul on Your Hand and Walk".
Hassouna was killed along with 10 relatives in an Israeli air strike on her family home in northern Gaza last month, the day after the documentary was announced as part of the ACID Cannes selection.
Farsi welcomed the impact of her film but called on Cannes Festival organisers to denounce Israel's ongoing bombardment of the devastated Palestinian territory.
"There needs to be a real statement," she told AFP. "Saying 'the festival isn't political' makes no sense."
This year's Cannes jury president Juliette Binoche was initially said by organisers to have signed the petition, but her spokeswoman told AFP that she had not endorsed it and her name was not published by Liberation.
Other signatories include Jonathan Glazer, the British director of Jewish origin who won an Oscar for his 2023 Auschwitz drama "The Zone of Interest", as well as US star Mark Ruffalo and Spanish actor Javier Bardem.


The Cannes Festival kicks off on Tuesday on the French Riviera, with an opening ceremony headlined by Robert De Niro and three films showing the devastation of Russia's war on Ukraine.
Two documentaries featuring Ukrainian President Volodymyr Zelensky and a third film shot on the brutal frontlines of Europe's biggest war in 80 years are to be screened on a "Ukraine Day" of programming.
It is "a reminder of the commitment of artists, authors and journalists to tell the story of this conflict in the heart of Europe", the festival said.
Nothing similar has been planned for the war in Gaza, but the film on Hassouna is set to "honour" her memory, organisers said previously.
Gazan filmmakers Arab and Tarzan Nasser are also set to showcase their fiction feature set in 2007 in the Palestinian territory in one of the secondary sections of the festival.
The opening film on Tuesday evening is "Leave One Day" by French director Amelie Bonnin, a newcomer, before Hollywood heavyweight De Niro receives an honorary Palme d'Or.


De Niro is one of the most outspoken critics of US President Donald Trump in the American cinema world, with the "Taxi Driver" star often struggling to find words harsh enough for the US president.
Trump has made himself one of the main talking points in Cannes after announcing on May 5 that he wanted 100-percent tariffs on movies "produced in foreign lands".
The idea sent shockwaves through the film world, although few insiders or experts understand how such a policy could be implemented.
Cannes director Thierry Fremaux talked up the festival's "rich" American film programme on Monday, with movies from Wes Anderson, Richard Linklater, Ari Aster and Kelly Reichardt in the main competition.
"American cinema remains great cinema. The United States remains a great country of cinema," he said.
Off-screen news in France is also likely to overshadow the red-carpet action in Cannes on Tuesday, with French film icon Gerard Depardieu facing a verdict in a sexual harassment case in Paris.
Depardieu, who has acted in more than 200 films and television series, is the highest-profile figure caught up in France's response to the #MeToo movement against sexual violence.


While independent cinema forms the core of the Cannes festival, organisers also hand over part of the programme to major Hollywood studios to promote their blockbusters.
Tom Cruise is set to return to the Riviera for the premiere of the latest instalment of his "Mission: Impossible" franchise on Thursday, three years after he lit up the festival while promoting "Top Gun: Maverick".
The festival will also see a series of high-profile debut films from actors-turned-directors, including "Eleanor the Great" from Scarlett Johansson and "The Chronology of Water" by Kristen Stewart.
Organisers on Monday denied reports that they had banned provocative near-nude dresses from the red carpet.
However, "full nudity on the red carpet" has been formally outlawed, "in keeping with French law".