The carnage in India served yesterday as an urgent and disturbing reminder to Barack Obama, the US President-elect, that the spectre of foreign terrorism is just as likely to challenge him in his first days in office as are the continuing stumbles of the domestic economy.

The attacks are deeply alarming to the United States. They were denounced simultaneously by President George Bush and the Obama transition team in Chicago. Events in India also seemed to give a measure of vindication to Vice President-elect Joe Biden who was criticised, not least by the Republican candidate John McCain, when he predicted weeks before voting that the "mettle" of Mr Obama would be tested within weeks of his taking office by an "international crisis". Just such a crisis seem to have arisen earlier than Mr Biden imagined.

The attacks, reported saturation-style on the US networks on Thanksgiving Day, were a reminder to ordinary Americans of the threat. Only this week, an FBI memo was leaked to the press, warning the authorities of possible attacks by al-Qa'ida on the New York subway before Christmas.

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"These co-ordinated attacks on innocent civilians demonstrate the grave and urgent threat of terrorism," an Obama spokesman, Brooke Anderson, said. "The United States must continue to strengthen our partnerships with India and nations around the world to root out and destroy terrorist networks."

There was no word of Americans being among those killed, witnesses in Mumbai said the terrorists had singled out Britons, Americans and also Israelis as they stormed the hotels. There is also an acute awareness that, in the seven years since 9/11, India has emerged as the most important ally to the US in the region, which may have made it a target for terrorism.

"If the terror threat spreads from Pakistan and Afghanistan to the important American ally, India, that's an enormous problem for the United States," David Gergen, an ex-presidential adviser and commentator warned.

For much of this week, Mr Obama has tried to reassure Americans that he is getting on top of the economic crisis, holding news conferences three days in a row in Chicago and rolling out the senior members of his economic team. The economy was also the focus of new media interviews, the most recent with Barbara Walters on Wednesday when he warned he was "no miracle worker".

The horror in India will now force him quickly to spread his focus also to international issues. Helping India recover from its trauma and bring the captured terrorists to justice as well as the broader issue of foreign-bred terrorism will now by necessity be at the top of his agenda. Already as candidate he spoke of a rapprochement between India and Pakistan as holding the key to winding up terrorism along the border with Afghanistan.