WASHINGTON, Oct. 5 (UPI) -- A allegation by Republican U.S. vice presidential nominee Sarah Palin that Barack Obama has ties with terrorists is "offensive," an Obama spokesman says. Palin, governor of Alaska and running mate of Republican U.S. presidential nominee John McCain, Saturday accused Obama, a U.S. senator from Illinois and McCain's Democratic opponent, of associating "with terrorists who targeted our own country." It was an apparent reference to Obama's dealings with University of Illinois at Chicago Professor William Ayers, who in 1969 co-founded the militant anti-Vietnam War group Weather Underground. Obama campaign spokesman Hari Sevugan told CNN Palin's comments...