The cleric behind plans to build an Islamic community centre near Ground Zero says he is still "exploring all options" over the project.
Imam Feisal Abdul Rauf said the plan would "bring honour to city of New York" and to Muslims around the world.
But speaking in New York he added that "everything is on the table" in a bid to "resolve this crisis".
Critics say building close to the site where almost 2,800 people were killed by al-Qaeda hijackers is offensive.
Thousands of people marched through New York on Saturday, on the ninth anniversary of the 11 September attacks, demonstrating both for and against the project.
The controversy over the cultural centre and mosque project was inflamed by a row over a Florida pastor's plans, later cancelled, to burn copies of the Koran on 9/11.
In remarks at the Council on Foreign Relations, Mr Rauf said he and the projects' other backers did not anticipate the outcry.
"We were surprised because when the news became public [in December 2009] nobody objected," he said.
He said if backers had known the level of protest it would provoke, they might have reconsidered.
On Sunday, Mr Rauf said the Koran-burning would have strengthened radical Islamic extremists and increased the danger of terrorist attacks against the US.
He also rejected claims by Terry Jones, the pastor behind the Koran-burning plans, that the bonfire was cancelled after Mr Rauf agreed to relocate the Islamic centre away from New York's Ground Zero.
"How can you equate the burning of any person's scripture with an attempt to build inter-faith dialogue?" Mr Rauf told ABC.
"This is a house with multi-faith partners, intended to work together towards building peace."