WASHINGTON (AFP) –- U.S. presidential candidates declared Monday a temporary truce as they vowed to take care of returning war veterans, ahead of a tense week that could see Barack Obama sew up the Democratic nomination.

While Obama and presumptive Republican nominee John McCain vehemently disagree over the Iraq war, both used the Memorial Day holiday to promise to do more to help soldiers returning from Iraq and Afghanistan gain medical care and education benefits.
""As president, I will do everything in my power to ensure that those who serve today and those who have served in the past have access to the highest quality health, mental health and rehabilitative care in the world,"" McCain said at an event in Albuquerque, New Mexico.
He admitted that despite his support for the war in Iraq, like many Americans, ""I, too have been made sick at heart by the many mistakes made by civilian and military commanders and the terrible price we have paid for them.""
The Vietnam war hero said however that ""we cannot react to those mistakes by embracing a course of action that will be an even greater mistake,"" namely pulling troops out of Iraq too soon.
The past week has seen sharp exchanges between McCain and Obama, a strong opponent of the war, including disagreement over a veterans bill.
But like McCain, Obama also held his fire Monday to pay tribute to members of the U.S. military. In a speech in New Mexico, he called on the government to give the same priority to helping veterans at home as to building a modern military.
""So on this day, of all days, let's memorialize our fallen heroes by honoring all who wear our country's uniform; and by completing their work to make America more secure and our world more free,"" Obama said.
""But let's also do our part -- service-member and civilian alike -- to live up to the idea that so many of our fellow citizens have consecrated -- the idea of America.""
As his Democratic rival Hillary Clinton offered similar sentiments while she campaigned ahead of the next contest in Puerto Rico on Sunday, Obama picked up two of former candidate John Edwards's delegates and three more superdelegates from Hawaii, adding to his growing lead in the marathon nomination battle.
Nearly six months since the costliest primary race in U.S. history kicked off in Iowa in early January, Obama leads with 1,973 delegates, compared to 1,780 for Clinton, according to RealClearPolitics.com.
The winning line is 2,026, leaving Obama on the cusp of becoming the first African-American selected as a major U.S. party's presidential standard bearer.
In the run-up to the Puerto Rico primary, and the climactic contests two days later in Montana and South Dakota, Clinton dismissed pundits who say her bid to secure the nomination from Obama is doomed.
""There isn't anything we cannot do together if we seek God's blessing and if we stay committed and are not deterred by the setbacks that often fall in every life,"" she told a church congregation in Hormigueros on Sunday.
Obama said earlier that Florida was the Clinton campaign's ""last slender hope to make arguments about how they can win.""
Next Saturday, at a meeting of the Democratic Party's rules committee, the Clinton campaign will press its case for the lion's share of convention delegates she won in Florida and Michigan to be reinstated.
McCain has already begun his hunt for a running mate, according to reports, spending this weekend at his Arizona ranch with three prospective candidates.