The meeting will consider steps to counter the threat, and to tighten security at governmental and other vital installations, according to an ABC News report anchored by Brian Ross.
He quoted government officials as saying the threat level is higher than at any time in the recent past; the Thursday meeting in the Situation Room of the White House is the latest, Ross reports, of a series that has been convened in light of new intelligence, and recent incidents in Glasgow and London.
Government officials told ABC News that the planners of the London attack had extensively used the Internet. This, in turn, has provided intelligence agencies vital clues, now being used to decode e-mails that had been originally overlooked.
US Secretary for Homeland Security Michael Chertoff told the media that the heightened threat perception has to do with increased 'chatter' and e-mail traffic, in addition to several new tapes released by Al Qaeda in recent weeks.
Ayman al-Zawahri, Al Qaeda's number 2 man, in a series of tapes, released on Tuesday, threatened fresh attacks against London, and
In an official statement, the White House meanwhile played down the level of threat without discounting it altogether. 'After the attempted terrorist attacks in the UK, the US government convened meetings to discuss the situation -- that is what citizens should expect.'
'There is no credible evidence of an imminent threat, however, and counter-terrorism officials regularly meet -- that is not unusual. We are taking all threats seriously and working to ensure we can keep the terrorists from striking at innocent people.'
Intriguingly, recent weeks have seen top Republicans issue veiled prophecies of terrorist attacks on America in the near future.
Former US Senator Rick Santorum of Pennsylvania, for instance, in an appearance on a radio show said terror attacks could occur in America, and that when it did, it could alter the current anti-war sentiment in a nation that has, per latest polls, returned a 28 per cent approval rating of President George W Bush, his lowest ever.
'Between now and November,' Santorum said, 'a lot of things are going to happen, and I believe that by this time next year, the American public's going to have a very different view of this war, and it will be because, I think, of some unfortunate events, that like we're seeing unfold in the UK.'