Obama, the Democratic U.S. presidential nominee and Illinois senator, is being targeted by his Republican opponent, Sen. John McCain of Arizona, for allegedly close ties to William Ayers, 63, a co-founder in 1969 of the Weather Underground militant anti-war group.

But an investigation by the Times indicated that while Obama has purposely minimized his dealings with Ayers, now a professor of education at the University of Illinois at Chicago, the men do not appear to have been close. Obama also has never expressed sympathy for the agenda of the Weathermen, who perpetrated a bombing campaign that killed a police officer, the newspaper reported.

Obama's contacts with Ayers mostly came in the latter's capacity as an activist for education reform in Chicago. Obama served on several of the same Chicago boards and organizations as Ayers, and traveled in the same political and social circles. But Obama never developed any personal ties with Ayers, the newspaper reported.

"The suggestion that Ayers was a political adviser to Obama or someone who shaped his political views is patently false," Ben LaBolt, a campaign spokesman, told the Times.