In a letter to President George Bush on Thursday, California Senator Dianne Feinstein said: "I want to express my profound dismay about reports that officials from your administration and your re-election campaign were 'heavily involved' in writing parts of Prime Minister Iyad Allawi's speech.
"You may be surprised by this, Mr President, but I viewed Prime Minister Allawi's speech as an independent view on conditions in Iraq," she wrote.
"His speech gave me hope that reconstruction efforts were proceeding in most of the country and that elections could be held on schedule.
"To learn that this was not an independent view, but one that was massaged by your campaign operatives, jaundices the speech and reduces the credibility of his remarks," Feinstein wrote.
Her letter was a response to an article appearing in Thursday's Washington Post, which also alleged that Allawi was coached by US officials - including Dan Senor, former spokesman for the US authorities in Iraq - in perfecting his delivery of the speech given before a joint session of congress a week ago.
"The unusual public-relations effort by the Pentagon and the US Agency for International Development comes as details have emerged showing the US government and a representative of President Bush's re-election campaign had been heavily involved in drafting the speech given to congress last week by interim Iraqi Prime Minister Allawi," wrote Washington Post journalists Dana Milbank and Mike Allen in the article.
A US newspaper says Allawi (L)
was coached by Bush officials
"Combined, they indicate that the federal government is working assiduously to improve Americans' opinions about the Iraq conflict - a key element of Bush's re-election message."
The article said Senor coached Allawi in New York.
Senor declined to comment.
In a Washington Post article on 28 September, Milbank also compared several key aspects of Allawi's speech to previous Bush speeches.
For example, while Allawi said "the world is better off without Saddam Hussein", Bush had said "the world is better off without Saddam Hussein in power" in one of his previous speeches.
And while Allawi said "it's a tough struggle with setbacks, but we are succeeding", Bush had said "it's tough at times ... but there is steady progress".