NEW YORK - Democratic presidential hopeful Barack Obama, who has been trying hard to convince his fellow Americans that he is not a Muslim, has asked those accompanying him on his current Middle East trip not to wear green, according to a media report. Politico, a website news service, said the move has created "wide puzzlement among observers of the Middle East". In a memo to reporters, described as "a few guidelines we sent staff before departure to the Middle East," Obama staffer Peter Newell laid out rules on attire for Jordan and Israel, the last two stops of his trip. First among them: "Do not wear green." An Obama aide explained to reporters that green is the colour associated with the militant Palestinian group Hamas, Politico said, noting that although the colour does appear on Hamas banners, green is more generally seen as a symbol of Islam. "A ban on wearing green seems bizarre," Richard Bulliet, a professor of Middle Eastern history at Columbia University, was quoted as saying. "I would hazard the guess that the campaign's concern is more with distorted"and religiously inaccurate"reporting by Obama's detractors than with any actual signal that might be conveyed," he said, referring to rumours that Obama is a Muslim. "You don't want to have some blogger come along and say 'Obama is showing his true colour.'" "I think they're just being overcautious to a ridiculous degree," Bulliet said. Mohamad Bazzi, a professor of journalism at New York University and former Middle East bureau chief for Newsday, called the instruction "very strange."  "I guess green is the 'Hamas colour' " but it's also the colour of Islam" Bazzi said in an email to Politico from Beirut. "That's one way for the Obama campaign to alienate 1.4 billion Muslims worldwide." Though the campaign's other sartorial instructions " directing women to dress demurely " are fairly standard, Bazzi said he'd never heard it suggested before that journalists not wear green while traveling in the Middle East.