A war of words with racial undertones marked the White House race yesterday after civil rights activist John Lewis accused Republican John McCain of sowing hatred against Barack Obama.
The latest political turbulence comes three weeks before the November 4 election, with Senator Obama building a steady lead over Senator McCain on the national level, and on the state-by-state electoral map.
It also overshadowed another controversy, the legislative probe finding in Alaska that state governor and Republican vice-presidential nominee Sarah Palin had abused her power in a feud with her ex-brother-in-law.
Mr Lewis, a US congressman revered as one of the key figures in the US civil rights movement, ignited a political firestorm by issuing a statement about Senator McCain's recent character attacks on Senator Obama.
''As public figures with the power to influence and persuade, Senator McCain and Mrs Palin are playing with fire, and if they are not careful, that fire will consume us all,'' Mr Lewis said.
Republicans ''are sowing the seeds of hatred and division, and there is no need for this hostility in our political discourse''.
He also appeared to suggest attacks on Senator Obama were reminiscent of late segregationist Alabama governor and presidential candidate George Wallace, whose rhetoric in 1963 was blamed for a church bombing in Birmingham, Alabama, that killed four little girls.
Senator McCain said Mr Lewis had launched a ''character attack against Governor Sarah Palin and me that is shocking and beyond the pale''. He said Mr Lewis's apparent reference to Mr Wallace was ''unacceptable and has no place in this campaign''.
Senator McCain called on Senator Obama ''to immediately and personally repudiate these outrageous and divisive comments''.
Later, Mr Lewis issued a second statement in an apparent attempt to defuse the row, saying he had not meant to draw a link between Mr Wallace and Senator McCain.
''My statement was a reminder to all Americans that toxic language can lead to destructive behaviour, I am glad that Senator McCain has taken some steps to correct divisive speech at his rallies,'' he said.
Chants of ''terrorist'' and ''kill him'' were reportedly heard at recent McCain Republican events and some commentators blamed hard-hitting negative advertisements which claimed Senator Obama consorted with a domestic ''terrorist'' 1960s radical William Ayers.
Some political commentators have questioned whether the seething resentment at Republican events could be a security threat for Senator Obama, who was offered Secret Service protection months before is normal for presidential candidates.
An Obama spokesman said the senator did not believe in the comparison between Senator McCain and Mr Wallace. AFP