Although the poll conducted by the Pew Research Centre termed the race for the White House to be still a statistical dead heat, it pointed out that voters were being increasingly impressed by the challenger.

The poll, conducted among a nationwide sample of 1512 adults, showed Kerry leading against Bush overall 47-45% with independent Ralph Nader at two percent support.

Kerry had a 52-37% lead over Bush when it came to voters' confidence in his ability to steer the economy, rising steadily from a five-point edge he enjoyed in March and a 10-point margin in May.

Bush slipping

The Pew findings also had good news for Kerry on the security front, once considered a strong point for the Republican incumbent who declared he was running for re-election as a "war president".

Kerry topped Bush 46-44% on who can better deal with Iraq, reversing a three-point lead for the president in May. On the war on terrorism, Kerry halved a 19-point Bush margin in May and trailed 39-49%.

Kerry also maintained a healthy lead on jobs, education and health care, but Bush was better viewed on a range of personal characteristics.

He led against Kerry 57-34% on strong leadership, 50-38% on judgment and 62-29% on willingness to take an unpopular stand if necessary. The president was also rated higher on honesty.

"John Kerry continues to hold a sizable lead over the president as the candidate best able to handle most domestic issues and has made considerable gains in terms of foreign and security issues as well," the survey said.

"But Bush maintains a clear advantage as the candidate with better leadership qualities in the eyes of most voters, and Kerry has not shaken the impression that he changes his mind too much."