Jane Fonda is expressing regret over endorsing a protest letter that targets an Israeli film spotlight at the Toronto International Film Festival.

The celebrity activist appears to back away from the controversy in a column posted Monday on the Huffington Post website just as big-name performers including Jerry Seinfeld, Natalie Portman and Sacha Baron Cohen added their names to a growing list of the protest's critics.

"I signed the letter without reading it carefully enough, without asking myself if some of the wording wouldn't exacerbate the situation rather than bring about constructive dialogue," Fonda writes in the article.

"In the hyper-sensitized reality of the region in which any criticism of Israel is swiftly and often unfairly branded as anti-Semitic, it can become counterproductive to inflame rather than explain and this means to hear the narratives of both sides, to articulate the suffering on both sides, not just the Palestinians. By neglecting to do this the letter allowed good people to close their ears and their hearts."

The letter was written by a group of Toronto-based filmmakers angered by the festival's decision to put Tel Aviv at the centre of its inaugural City to City program. The group held a press conference Monday to explain their concerns and to refute claims they advocate a boycott.

It is not the films or the filmmakers we protest but rather the frame," said filmmaker Elle Flanders, who spoke alongside Toronto filmmaker John Greyson and Palestinian-Israeli director Elia Sulieman, among others.

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."

The flap has drawn heated opposition from celebrity critics, which on Monday grew to include Portman, Cohen, and Seinfeld among dozens of people that endorsed a statement applauding 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."

Protest organizers said they had collected more than 1,500 signatures for their letter, including from historian Howard Zinn, filmmaker Guy Maddin and actor Viggo Mortensen, in addition to early signers author Naomi Klein 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 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.