More than 255,000 people have signed a petition on the Downing Street website against any plans to build Britain's biggest mosque in East London.
The Downing Street petition site was launched last year
The petition, currently the most popular on the No 10 site, calls for the "mega mosque" to be scrapped as it will "cause terrible violence".
But London mayor Ken Livingstone said it was part of a "vicious" campaign to spread untruths about the scheme.
No 10 is expected to respond when the petition closes on Wednesday.
It has resisted calls to remove the petition from its site, amid claims racist language had to be removed from the list of signatories.
The row centres on plans by Tablighi Jamaat to build a 12,000 capacity mosque on land in West Ham.
Downing Street has said any planning decision will be down to the local authority but Newham Council is not expecting to receive a planning application for a mosque "in the near future".
Tablighi Jamaat has said it is pushing ahead with the scheme and last week appointed architects Allies and Morrison, whose previous projects include The Royal Festival Hall and the BBC's White City media village.
"The development will include the largest mosque in the UK, with a capacity of 12,000 but it will also include a new school and conference centre," said Abdul Sattar Shahid, of Tablighi Jamaat, in a statement.
"We look forward to welcoming our neighbours in Newham and visitors from elsewhere in London when the development opens."
A spokesman denied the Abbey Mills mosque plans amounted to a "mega mosque", adding it would cost between £50m and £75m not the £100m claimed by opponents.
But he said the group did not feel under pressure to respond to the Downing Street petition, as the wording of it was "factually inaccurate".
'No public funding'
The petition says: "We the Christian population of this great country England would like the proposed plan to build a Mega Mosque in East London scrapped. This will only cause terrible violence and suffering and more money should go into the NHS."
But the spokesman for Tablighi Jamaat said it was wrong to suggest the money should go into the NHS as there "has never been a request for public funding" for the Abbey Mills project.
London mayor Ken Livingstone attacked what he called a "vicious" campaign of misinformation against the mosque.
"There are not now, and have never been, any plans by the Mayor or Greater London Authority to spend any public money on such mosque. Indeed, it would be illegal for the Mayor of London to do so.
"Suggestions of a link between plans for a mosque and the 2012 Olympic Games are equally untrue, as are suggestions of the enormous size of any planned mosque."
He added: "The circulation of these manifestly untrue reports seems to be designed to bring influence to bear on a petition in relation to such a mosque on the No 10 Downing Street website."
The Downing Street petition was posted under the name Jill Barham, although attempts to contact her have so far proved unsuccessful.
Local opposition to the mosque has been led by councillor Alan Craig, of the Christian People's Alliance, who has raised concerns about its impact on the local community.
But Mr Craig distanced himself from the Downing Street petition, saying he had not signed it and did not know who was behind it.
"It shows the strength of public feeling but the wording of it is not very helpful and not very accurate," he told the BBC News website.
Earlier this year, the Downing Street website was at the centre of controversy after it received 1.8m e-mails calling for road pricing trials to be stopped.