One of Barack Obama’s Middle East policy advisers disclosed yesterday that he had held meetings with the militant Palestinian group Hamas – prompting the likely Democratic nominee to sever all links with him.

Robert Malley told The Times that he had been in regular contact with Hamas, which controls Gaza and is listed by the US State Department as a terrorist organisation. Such talks, he stressed, were related to his work for a conflict resolution think-tank and had no connection with his position on Mr Obama’s Middle East advisory council.

“I’ve never hidden the fact that in my job with the International Crisis Group I meet all kinds of people,” he added.

Ben LaBolt, a spokesman for Mr Obama, responded swiftly: “Rob Malley has, like hundreds of other experts, provided informal advice to the campaign in the past. He has no formal role in the campaign and he will not play any role in the future.” The rapid departure of Mr Malley followed 48 hours of heated clashes between John McCain, the Republican nominee-elect, and Mr Obama over Middle East policy.

Mr Obama, who has been trying to assuage suspicion towards him among the influential Jewish and pro-Israel lobby, spoke at a Washington reception marking the 60th anniversary of Israeli independence on Thursday when he promised that his commitment to the country’s security would be “unshakeable”. However, Mr McCain has high-lighted the Democrat’s pledge to negotiate directly with nations such as Iran – whose leaders talk of wiping Israel off the map – and a statement from Hamas saying that it hoped that Mr Obama would win the presidency.

This was denounced as an offensive smear by Mr Obama, who repeated earlier statements saying that Hamas was “a terrorist organisation [and] we should not negotiate with them unless they recognise Israel, renounce violence”.

He went on to suggest that Mr McCain’s attack showed that he was “losing his bearings”. This remark triggered a furious reaction from Mark Salter, the Republican’s senior adviser, who said that Mr Obama was “intentionally raising John McCain’s age as an issue” – a claim the Democrat vehemently denied. The intensity of this dispute reflects both Mr Obama’s desire to move beyond his battle with Hillary Clinton and how Republicans are already beginning to train their sights on him.

The Republican National Committee has amassed a 1,000-page dossier on Mr Obama, with researchers spending weeks in Chicago seeking fresh material. He is already being criticised for his links with Rashid Khalidi, a Columbia University professor who has branded Israel an “apartheid system in creation”.

Mr Malley, a respected commentator on Middle Eastern issues and part of President Clinton’s negotiating team at the Camp David talks, has come under attack in recent months from right-wing bloggers. Yesterday, asked if Obama campaign was aware of his contact with Hamas, he said: “They know who I am but I don’t think they vet everyone in a group of informal advisers.”

Randy Scheunemann, Mr McCain’s foreign policy chief, suggested that Mr Malley was part of an emerging pattern in which other advisers had been repudiated after throwing confusion over policies on trade and Iraq. “Perhaps because of his inexperience Senator Obama surrounds himself with advisers that contradict his stated policies,” he said.

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