Hillary Clinton's camp was seething yesterday over what it sees as a snub by Barack Obama in appointing a former staffer with whom she has fallen out to a key post in his campaign team.

"This is a stick in the eye to her," one of her inner circle said, adding that it effectively ruled Clinton out as his vice-presidential running mate.

The clash comes only a fortnight after Obama and Clinton held a private hour-long chat in Washington at the end of a long and acrimonious primary contest. Neither spoke publicly afterwards but the new appointment indicates that the meeting failed to repair relations.

Obama, announcing on Monday his enlarged campaign team for the November 4 presidential election, appointed Patti Solis Doyle, Clinton's former campaign manager, as chief of staff for the vice-presidential candidate. Clinton, having failed to win the Democratic presidential nomination, has been pushing to become vice-presidential candidate but Obama is reluctant to make the offer.

Clinton has been estranged from Solis Doyle since she sacked her earlier this year, blaming her for mismanaging funding and for ignoring the caucuses that gave Obama a lead that proved to be decisive.

The source in her team said: "It creates a bad taste. It is very counterproductive. A foolish political move ... Choosing her as chief of staff to the vice-presidential nominee - someone that [Clinton] has not chosen and whom she removed - is a way of saying Hillary Clinton is not going to be the vice-president."

Obama's public position is that no one has been ruled out in the search for a vice-presidential candidate. He has established a small team to vet candidates, and the list of potential running mates is long.

After the Washington meeting, Senator Dianne Feinstein, who provided her home for the two to meet, said they appeared happy. Two days later, Clinton made a speech in Washington conceding the race and endorsing Obama. But since then there has been no reciprocal conciliatory move by Obama. As well as not offering her the vice-presidential slot, he has not yet proposed a joint public appearance with her or with Bill Clinton.

The Obama team does not want her on the ticket, in spite of her accumulating 18m votes during the campaign and being more successful than him in attracting women, Latinos and white working-class males. It fears she and her husband could be divisive, operating as an alternative power base in the White House. There is also lingering resentment inside Obama's camp from the primaries, blaming Bill Clinton for making race an issue.

The strain between the two camps is undermining attempts to reunite the Democratic party. Some of Clinton's supporters and donors have said they will not switch their support to Obama. Clinton is scheduled to hold a conference call today with her donors urging them to switch funding to Obama.

A poll by the Washington Post/ABC published yesterday recorded that 46% of Democrats favoured Clinton as the vice-presidential candidate. No other potential running mate made it out of single digits. The poll puts Obama ahead of the Republican candidate John McCain by 48% to 42%. Among independents, who could hold the key to the election, the two candidates are about even.

The main issue of the day was energy policy, dominated by a speech by McCain in which he proposed extending drilling for oil in US waters. Obama accused him of pandering to the interests of the major oil companies.

McCain, who is popular with some environmentalists because he was early among US politicians in accepting the climate change argument, aired ads yesterday distancing himself on climate change from George Bush, whose unpopularity is a drag on his candidacy. Pro-Democratic groups paid for a counter-ad showing a woman with a baby saying she did not want McCain to send her child to Iraq.