This aerial photo shows the site where the twin towers of the World Trade Centre collapsed. The proposed mosque would be built two blocks away, in the lower right area of the photo. (Mark Lennihan/Associated Press)

Efforts to build a mosque two blocks from the site of the 9/11 attacks in lower Manhattan got a big boost Tuesday when a city agency cleared the way for the construction of a controversial Muslim cultural centre.

New York's City Landmarks Commission announced it would not give an old building on the site landmark status to protect it from demolition.

That allows the building to be torn down to make way for a 13-storey Islamic centre that has sparked heated opposition from critics who say its presence so close to the site of the World Trade Centre attacks would insult the memory of the 3,000 who died there.

The $100-million US Cordoba House complex includes a mosque, cultural centre, auditorium and prayer room.

Critics had tried to block the project by getting a nearby building declared historic. They'd argued that the building should be protected because it had been hit by some of the wreckage from the planes that hit the twin towers.

The commission voted unanimously, however, that the building was not historic.

Site inappropriate, critics say

Ever since plans for the Islamic centre surfaced, fierce opposition has emerged from those who've said the centre should not be built so close to the spot where Islamic extremists engineered the worst terrorist attack on American soil.

Critics have openly wondered where the funding for the massive project is coming from.

The mosque is a project of the American Society for Muslim Advancement and the Cordoba Institute, which promotes cross-cultural understanding between Islam and the west.

Others have speculated that the centre's motives may not be as benign as its leaders claim — noting that the director of the Cordoba project has been quoted as saying U.S. policies contributed to the Sept. 11 attacks.

The project has also divided politicians. New York Mayor Michael Bloomberg supports the mosque, while Rick Lazio, a former Republican Congressman who's running for governor, opposes it.

With files from The Associated Press