One ad, featuring the actor Paul Giamatti, ran with the line: "Just another family man making a living." Another showed Clive Owen pointing two pistols at the viewer.
Entertainment Film Distributors, which ran the ads, said the posters had been approved by the Advertising Viewing Committee of the Film Distribution Association.
The ASA ordered that two of the three posters should not be shown again. In its adjudication, the regulator stated it is "mindful of growing levels of public concern about the use and threatened use of guns".
In another ruling, the ASA rejected complaints that a press ad for Debenhams, featuring models standing on a railway crossing, was irresponsible. Eight complainants felt the ad could encourage dangerous behaviour on the railways, but the ASA found the ad used "a stylised image sufficiently moved from reality".
The ASA did agree an ad for npower by Beattie McGuinness Bungay, with the line "npower, the green energy behind concerts at Wembley Stadium", could be misleading since it implied the energy for Wembley came from renewable sources. It will not be shown again in its current form.