Artists angered by a spotlight on Israeli films at the Toronto International Film Festival insisted Monday they are not calling for a boycott as they continued to draw the ire of a growing list of celebrity critics.

Filmmakers including Toronto's John Greyson, Elle Flanders and Palestinian-Israeli director Elia Sulieman held a press conference to refute charges they were blacklisting the festival's "City to City" program and its participants.

"It is not the films or the filmmakers we protest but rather the frame," Flanders said of the film festival event, which focuses on movies from Tel Aviv.

"Our campaign was meant to begin the dialogue that Tiff missed out on -- one that refuses the Israeli government's attempt to shift attention away from the conflict that it maintains and worsens daily."

Flanders complained that the spotlight excludes Palestinian voices, comes on the heels of a devastating bombardment in Gaza and amid a global publicity campaign by the Israeli government known as "Brand Israel."

But the assertions came just as the group's critics grew to include celebrities Natalie Portman, Sacha Baron Cohen, Jerry Seinfeld, and Lisa Kudrow. The high-profile performers were among those to endorse a statement released Monday that applauded the "City to City" program and denounced notions of a blacklist.

"Anyone who has actually seen recent Israeli cinema, movies that are political and personal, comic and tragic, often critical, knows they are in no way a propaganda arm for any government policy," said the statement, also endorsed by Lenny Kravitz, Patricia Heaton, Jacob and Noah Richler, George F. Walker and Moses Znaimer.

"Blacklisting them only stifles the exchange of cultural knowledge that artists should be the first to defend and protect."

Greyson withdrew his film from the festival in protest but said he in no way encouraged others to do the same, nor did he wish anyone blacklist participants.

"From the start we encouraged others to speak out in whatever way they chose, which they have, by the many hundreds," said Greyson, reading from a statement structured as a letter to producer Robert Lantos, one of the group's biggest critics.

"The last time I checked, this was called free speech."

Organizers said they had collected more than 1,500 signatures for their protest letter, including from historian Howard Zinn, filmmaker Guy Maddin and actor Viggo Mortensen, in addition to early signers author Naomi Klein, actress Jane Fonda and musician David Byrne.

Tel Aviv is the first city selected for the festival's "City to City" program, meant to spotlight the films from a particular urban centre.

While acknowledging the Tel Aviv's troubled history, festival co-director Cameron Bailey has defended the choice, saying the program was meant to foster debate and share in the exchange of cultures.

The film festival runs through Saturday.