A crack team of cybernauts will form a rapid response internet “war room” to track and respond aggressively to online rumours that Barack Obama is unpatriotic and a Muslim.

As he gears up for his general election fight against John McCain, Mr Obama and his chief advisers are aware of the danger of such rumours, amid polling data showing that a significant number of Americans believe he is a Muslim or are suspicious about his background. Such doubts were a factor in his poor showing with white, blue-collar voters during his primary battle with Hillary Clinton.

In recent days Mr Obama has — unprompted — brought up the subject of the chain e-mails and blog sites making the false claims. Some state that he is a radical Muslim who was sworn in as a US senator on the Koran; others that he sympathises with Palestinian radicals. Many focus on his middle name of Hussein, which was taken from his Kenyan father.

Mr Obama referred to the e-mails in a speech last week to AIPAC, the powerful Jewish lobby.

Mr Obama said: “They are filled with tall tales and dire warnings about a certain candidate for president and all I want to say is, ‘Let me know if you see this guy named Barack Obama because he sounds pretty scary’.”

Jen Psaki, a spokeswomen for Mr Obama, told The Times that the internet team was still being finalised.

She added: “The only way to run a campaign is to respond immediately when inaccurate information is put out. The [the e-mails] are saying he’s a Muslim. He’s not.

“He’s a Christian. He often brings up the e-mails that are out there and the smear campaign that’s been run against him on the internet.”

The “war room” comes as the Obama campaign prepares a series of biographical speeches, television advertisements and campaign appearances to tell his life story, an attempt to make voters more familiar with him. Despite his long nomination fight against Mrs Clinton, his campaign aides concede that millions of Americans still feel that they do not really know him.

Mr Obama’s Kenyan father, who left the family when he was 2, was a Muslim, but not particularly religious. The Illinois senator lived in Indonesia from the age of 6 until 10 with his white, American mother and Indonesian stepfather, who was a Muslim.

Mr Obama has never been a Muslim, or worshipped at a mosque. He moved from being agnostic to finding Christ in his 20s, with the help of his former Chicago pastor: the Rev Jeremiah Wright, a figure whose incendiary sermons now haunt his candidacy and has increased suspicions among some voters about his patriotism.

A poll in mid-March found that 13 per cent of Americans think that Mr Obama is a Muslim — a 5 per cent increase since December 2007. Another found that 23 per cent of Democrats who hold negative views of him believe that he is a Muslim. The same survey showed that 61 per cent of voters view him as patriotic, compared with 76 per cent for Mrs Clinton and 90 per cent for Mr McCain.

Senior aides to Mr Obama have opened talks with the Clinton camp to discuss pooling their formidable fundraising talent. Between them the two Democrats raised nearly $500 million (£254 million) during their nomination fight.

David Plouffe, Mr Obama’s campaign manager, is due to give a presentation to some of Mrs Clinton’s top fundraisers in New York on Thursday.

In recent weeks Mr Obama has also pinned an American flag badge to his suit lapel after being criticised by Republicans for not wearing one.

He locked horns with Mr McCain yesterday over the faltering economy, the number one issue with voters, as the Democrat started a 17-day economics tour with a speech in North Carolina lambasting the Republican over his support for the fiscal policies of President Bush.

The Arizona senator pre-empted his rival’s address by painting him as a liberal tax-and-spender.

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