Democratic presidential hopeful Barack Obama looks out on a sea of supporters at a campaign rally on the banks of the Willamette River in Portland, Ore., on Sunday. (Greg Wahl-Stephens/Associated Press)Ahead of Tuesday's primaries in Oregon and Kentucky, Democratic presidential hopeful Hillary Clinton warned her rival Barack Obama that the race for the party's nomination is "nowhere near over."

Obama, who holds a significant lead in delegates going into Tuesday's contests and is favoured to win the Democratic nomination, has instead focused on targeting presumptive Republican candidate John McCain.

Obama and McCain have been exchanging salvos on each other's foreign policy positions, effectively ignoring Clinton, who suggested the Illinois senator was getting ahead of himself by acting as if he had already secured the Democratic nomination.

Democratic presidential hopeful Hillary Clinton is hugged by her husband, former U.S. president Bill Clinton, as he introduces her during a campaign rally in Louisville, Ky., on Monday. (Elise Amendola/Associated Press) "You can declare yourself anything, but if you don't have the votes, it doesn't matter," Clinton said Monday during a television interview while campaigning in Kentucky, where polls indicate she is expected to win Tuesday. Meanwhile, Obama is heavily favoured to win Oregon.

"So I'm going to make my case and I'm going to make it until we have a nominee, but we're not going to have one today and we're not going to have one tomorrow and we're not going to have one the next day," Clinton added.

Despite last week's resounding defeat to Clinton in the West Virginia primary, Obama holds a near-unassailable lead in delegates who will choose the party's presidential nominee at the Democratic National Convention in August in Denver.

His campaign was also bolstered last week by the endorsement of former rival and 2004 vice-presidential candidate John Edwards.

The remaining Democratic primaries end June 3 with votes in Montana and South Dakota.

On Monday, Obama struck out at McCain after the Arizona senator accused him of displaying "inexperience and reckless judgment" for saying Iran does not pose the same serious threat to the United States as the Soviet Union did in its day.

Speaking in Montana, Obama countered that while the threat from Iran was indeed "grave," it had grown as a result of the U.S. war in Iraq, which McCain vehemently supported.

"Iran is the biggest single beneficiary of a war in Iraq that should have never been authorized and should have never been waged," he said. "And John McCain wants to double down that failed policy."

Obama camp reaches out to Clinton

Clinton also has tried to make the case that if the results of disputed primaries in Michigan and Florida are included, she would lead Obama narrowly in the overall popular vote.

The New York senator won both contests, but the results were voided because they took place in January, in violation of Democratic Party rules. Obama and three other Democrats, but not Clinton, removed their names from Michigan's ballot after all the Democratic candidates agreed not to campaign there or in Florida.

Meanwhile, one of Obama's top strategists reached out to Clinton's former campaign manager about joining forces for the general election, indicating a possible move toward reconciliation following the often-rancorous Democratic primary campaign.

Obama strategist David Axelrod and former Clinton aide Patti Solis Doyle confirmed they had had informal conversations about how she might help Obama if he secures the presidential nomination as expected.

"When the time comes, if we're the nominee, we're going to want to work with talented people across the party including those who worked for Senator Clinton," Axelrod said. "Patti's a good and talented person, and we all have a high regard for her."

He added, "No specific offers have been proffered, and none has been accepted. This is not an official entreaty from one campaign to another."

With files from the Associated Press