Barack Obama erased Hillary Rodham Clinton’s once imposing lead among superdelegates in their epic race for the Democratic nomination and turned his attention to the expected campaign against Republican John McCain.

Barack Obama’s campaign apologised to Hillary Clinton today after one of his key foreign policy aides branded the former first lady a desperate “monster”.

The close two-way race to become Democratic US Presidential candidate has landed party leaders with an unexpected problem over states barred from the contest.