A survey in the Los Angeles Times showed Mr Clinton leading Mr Bush by 49 per cent to 41 per cent, compared with a 56-33 advantage in an earlier poll. Mr Clinton has led by 30 or more points at times in the period between the Democratic convention in July and the Republican convention last week.
'The new results suggest Bush did what he desperately needed to at his party's convention - improve his image, sully Clinton's and get back in the race,' the newspaper commented.
A Newsweek poll said that if the 3 November elections were held today, Mr Clinton would win by 53 per cent to 39 per cent for Mr Bush, a difference of 14 points.
A Time/CNN poll showed Mr Clinton's lead over Mr Bush slipping from 27 to 11 points in the past month. Despite a 61 per cent approval rating for the President's handling of foreign policy, only 22 per cent of participants in the Time/CNN poll said he was doing a good job handling the economy, and 54 per cent said he did not deserve to be re-elected.
The Times poll revealed that Mr Bush made most of his gains among Republicans. He gained almost no ground among voters who identified themselves as independents.
Many of those polled were dis-satisfied with the Bush administration, with two-thirds believing the country is on the wrong track, and almost half saying the United States was in a serious recession.
Mr Clinton and his presidential running mate, Al Gore, continued the Democratic campaign yesterday with a new salvo: 'President George Bush is not to be trusted.'
In an attempt to claw back some ground, Mr Clinton went on the attack, reciting a litany of promises he said Mr Bush had broken, should not keep and could not keep.
At the first stop of a tour that will take them through Ohio, Pennsylvania and New York State, Mr Clinton told a crowd in Cleveland: 'This election is about trust. And we don't have to read his (Bush's) lips - we can read his record.'
He told a crowd of several thousand: 'Now that he has given us the greatest deficit in history . . . he wants to sucker punch us one more time by promising you a tax cut. If you believe that, I have some land in the middle of the ocean I want to sell you.'
Mr Bush, in his speech accepting the Republican nomination, proposed an across-the-board tax cut provided it was accompanied by spending cuts he felt were appropriate - a proposal Mr Clinton called 'fool's gold'.
'It was a cover-up - a cheap cover-up,' he said. 'We're not manipulating you for a cheap political advantage.'