The imam heading a planned mosque near the New York site of the 11 September 2001 terrorist strikes said late on Tuesday he has been awed by controversy over the project and vowed to "clearly identify" its financial backers.

He stressed the project in lower Manhattan was continuing and that he was well aware of the challenges in completing the so-called Cordoba House, a $100-million centre which has stirred raw emotions here.

"We have all been awed by how inflamed and emotional the issue of the proposed community centre has become," Cordoba Initiative chairperson Feisal Abdul Rauf, who recently returned from a two-week State Department-sponsored cooperation tour of the Middle East, wrote in an opinion piece on The New York Times website.

"The level of attention reflects the degree to which people care about the very American values under debate: recognition of the rights of others, tolerance and freedom of worship."

An uproar has swelled over the proposed Islamic cultural centre two blocks from where the World Trade Center once stood, and a slew of top political figures, from President Barack Obama to prospective 2012 Republican presidential candidate Sarah Palin have weighed in on the debate.

Rauf cited the "wonderful outpouring of support," including from New York Mayor Michael Bloomberg.

"It was striking: a Christian president and a Jewish mayor of New York supporting the rights of Muslims," Rauf wrote.

"Their statements sent a powerful message about what America stands for, and will be remembered as a milestone in improving American-Muslim relations."

A late August poll by Quinnipiac University showed New York voters, by a 71-21 percent margin, overwhelmingly do not want a new mosque built near the Ground Zero site.

"I do not underestimate the challenges that will be involved in bringing our work to completion. (Construction has not even begun yet.) I know there will be interest in our financing, and so we will clearly identify all of our financial backers," Rauf wrote.

US lawmakers including Republican Representative Peter King of New York and independent US Senator Joseph Lieberman have sought evaluation of the sources of funding for the project, a 13-story glass and metal building that will house a swimming pool, daycare, lecture hall, and prayer rooms.

The New York municipal council in May approved construction of the Islamic centre, setting off a national debate because of its proximity to where al-Qaeda hijackers brought down the Twin Towers, killing almost 3000 people nearly nine years ago.