Half (49.3%) of New York City residents and 41% of New York state citizens say some US leaders "knew in advance that attacks were planned on or around 11 September 2001, and that they consciously failed to act."

According to the poll, 66% in New York would like to see a new probe into the "still unanswered questions" surrounding the attacks on the World Trade Center and Pentagon.

The poll was conducted on the eve of the Republican National Convention which is being held in the city.

The Republican convention will use images from the 11 September  2001 attacks in an attempt to boost support for President George Bush, who is being challenged by Democratic presidential candidate John Kerry.

Fed up with silence

The poll was commissioned by W David Kubiak, executive director of 911truth.org.

Kubiak said the poll proved New Yorkers had unanswered questions on the attacks.

"I think these numbers show that most New Yorkers are now fed up with the silence, and that politicians trying to exploit 9/11 do so at their peril. The 9/11 case is not closed and New York's questions are not going away," Kubiak told the Zogby International website.