Hundreds of demonstrators lined up in New York on Sunday to protest against - and in favour of - a proposed Islamic community centre and mosque near Ground Zero, media reports said.
Broadcaster CNN quoted police as saying that by 11.30 local time (1630 GMT) supporters of the centre numbered up to 250 and critics made up some 450, dpa reported.
Signs against the proposed centre read, amongst other slogans, "Stop Sharia (Islamic law) before it stops you" and "Preserve the dignity of our loved ones killed on 9/11."
Supporters of the right of the Islamic organisation to build near the Ground Zero site accused the opponents of racism.
Police erected barriers and took preventative security measures, but no clashes were reported.
The Cordoba Institute, headed by long-time New York resident Imam Feisal Abdulrauf bought the run-down building at 45-47 Park Place, a former textile factory, in 2009 and began holding prayer services there.
President Barack Obama spoke out in favour of religious freedom in relation to the mosque controversy, but later tempered his remarks after Republican criticism.