Barack Obama was forced to shift his focus away from the economy and defend his national security credentials today following damaging remarks by his running mate — and as al-Qaeda unexpectedly thrust itself into the US election.

Mr Obama convened a carefully choreographed meeting of his national security team to shore up his foreign policy standing as his rival, John McCain, received the strange and unwelcome endorsement from a prominent al-Qaeda supporter. The extremist claimed the terror group would welcome a presidential victory for the Republican because he would continue the wars in Iraq and Afghanistan.

Mr Obama, who has seen a surge of support because of voter concerns about the economic crisis, had the subject of national security largely thrust upon him by clumsy remarks by Joe Biden, his running mate. The Delaware senator warned that America’s enemies will generate a “major international crisis to test the mettle” of Mr Obama in the first months of his administration, comments seized upon by John McCain and Sarah Palin.

It emerged today, however, that al-Qaeda supporters have been posting internet messages in recent days hoping for a victory by Mr McCain, even saying they would welcome a pre-election terror attack on the US because it could tip the election the Republican’s way.

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One message, posted on the extremist website al-Hesbah — which is closely linked to al-Qaeda — said that if the terror group wants to exhaust the US economically and military, then victory for the “impetuous” Republican candidate would benefit them because Mr McCain would continue “the failing march of his predecessor” President Bush.

The message was posted by Muhammad Haafid, a longtime contributor to the website. He has no direct affiliation to al-Qaeda, making it unclear whether he reflects the views of Osama bin Laden — who has not been heard of for six months — or anyone else in the terror organisation. While Mr McCain fiercely opposes a timetabled withdrawal from Iraq, he has pledged to end the war within four years.

The web commentary was one of several from al-Qaeda or Taleban-allied groups in recent days revelling in the global financial crisis and predicting a decline in power for the US and other Western governments. It comes almost exactly four years after bin Laden issued a videotape just days before the 2004 election directly addressing the American people, a scare tactic by the al-Qaeda leader considered helpful to Mr Bush on Election Day.

The comments by Mr Biden, a man known for his propensity to place foot in mouth, were unhelpful because polls suggest voters still harbour significant doubts about Mr Obama’s readiness to be commander-in-chief, a problem the campaign hoped had been reduced by the endorsement of the Democrat on Sunday by Colin Powell, the retired four-star general and former Republican Secretary of State.

Mr Obama said his running mate “sometimes engages in rhetorical flourishes but his core point was the next president is going to be tested regardless of who it is.” Mr Obama said that despite the enormity of the economic crisis, it was important to “not lose sight of the fact that we remain threatened” on national security. He said he wanted to check in with senior advisers to make sure he was “keeping pace with a moving target.”

New polls yesterday continued to show the uphill struggle faced by Mr McCain, and that Mrs Palin is now a greater liability to the Republican ticket than President Bush.

The widely respected NBC/Wall Street Journal national poll gave Mr Obama a 10-point lead, 52 to 42. It showed that Mrs Palin’s unfavourable ratings had risen 10 points in three weeks, up to 47 per cent — with just 38 per cent holding a positive view of her — and that 55 per cent do not believe she is qualified. The greatest concern voters now have about Mr McCain, according to the survey, was his choice of running mate.

The Republican’s road to victory has significantly narrowed in recent weeks. He appears to be banking all on victory in Pennsylvania — where he is eight points behind — and successfully defending six other “toss-up” states won by President Bush.

At a rally yesterday Mr McCain cast himself as a defiant underdog, declaring: “It doesn’t matter what the pundits think or how confident my opponent is.”

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