A Palestinian militant organisation that was ridiculed in the new Sacha Baron Cohen film has threatened to "respond in the way we find suitable" against the London-born satirist.

The al-Aqsa Martyrs Brigade, the armed wing of the Fatah movement, has condemned the film, Bruno, in which Cohen plays a gay Austrian fashionista, as "part of a conspiracy" against them. There was no comment from Cohen.

In the film, Cohen attempts to get himself kidnapped and arranges a meeting with Ayman Abu Aita, who, it is claimed, is a leader in the Martyrs Brigade, which is designated as a terrorist group in the US and European Union. While promoting the film, Cohen spoke of the clandestine meetings at shadowy locations and bodyguards required to set up the scene.

Cohen tells Abu Aita: "I want to be famous, and I want the best guys in the business to kidnap me," before adding: "Al-Qaida are so 2001". He then advises Abu Aita to shave off his moustache, "because your King Osama looks like a kind of dirty wizard or homeless Santa".

According to Abu Aita and the Martyrs Brigade, Abu Aita is not a member of the organisation, although he reportedly has had links in the past. He is a political representative for the Fatah party in Bethlehem and a board member of the Holy Land Trust, a non-governmental organisation promoting Palestinian rights with a commitment to non violence. He said it took a couple of phone calls for Cohen to locate him, and that the meeting was held in a private section of a popular restaurant.

While Abu Aita is pursuing legal action, the Martyrs Brigade issued a statement, through Jerusalem-based journalist Aaron Klein, of the WorldNetDaily website, saying: "We reserve the right to respond in the way we find suitable against this man. The movie was part of a conspiracy against the al-Aqsa Martyrs Brigade.

"According to what we checked, there was no meeting about the real context of the film. This was a dirty use of our brother Ayman." The statement added Abu Aita was not a member of the Brigades. "And we don't accept that the name of the al-Aqsa Martyrs Brigade is part of the film".

Abu Aita has said he does not carry weapons, and the person who accompanied him to meetings with Cohen was not a bodyguard but the American manager of the Holy Land Trust.