Washington  - Barack Obama spoke by telephone Monday with former president Bill Clinton, the first conversation between the two Democratic Party leaders since Obama clinched his party's nomination last month over Hillary Clinton.

Bill Clinton drew criticism as a sometimes bitter critic of Obama during the long nomination race with his wife, in particular for some racially charged comments discrediting Obama's victory in January's South Carolina primary.

Senator Obama had a terrific conversation with President Clinton and is honored to have his support in this campaign," Obama spokesman Bill Burton said in a statement.

Clinton campaigned aggressively for his wife but has yet to formally endorse Obama, though he has issued a statement in support of the presumptive Democratic nominee.

Former first lady Hillary Clinton endorsed Obama in early June and appeared with the Illinois senator last week at a joint rally.

It is unclear exactly what kind of role her husband will play in Obama's bid for the White House. Burton said that Clinton will be out campaigning for Obama, who is vying to become the nation's first African-American president.

Obama "has always believed that Bill Clinton is one of this nation's great leaders and most brilliant minds, and looks forward to seeing him on the campaign trail and receiving his counsel in the months to come," Burton said. (dpa)