A member of an honour guard helps U.S. President Barack Obama (L) lay a wreath in honor of Memorial Day at the Tomb of the Unknowns in Arlington National Cemetery in Arlington, Virginia, May 28, 2012. REUTERS/Jonathan Ernst

President Barack Obama was paying tribute to the nation's fallen warriors on Memorial Day, attending a ceremony at Arlington National Cemetery and honouring those who died during the Vietnam War.

For the first time in nine years, Americans “are not fighting and dying in Iraq,” Obama said in a speech at Arlington National Cemetery, after laying a wreath at the Tomb of the Unknowns.

But he noted that small groups of mourners can be seen at the cemetery daily, saying the grounds are “home to Americans from every part of the country who gave their lives in every part of the globe.”

The president also was set to mark the 50th anniversary of the Vietnam War at the Vietnam Veterans Memorial.

Republican challenger Mitt Romney was scheduled to appear in San Diego, home to a large number of military personnel and veterans.

In an election year, Obama has touted his work to bring U.S. combat troops home from Iraq and wind down the conflict in Afghanistan. Before military audiences and in a campaign ad released last week, he credits U.S. servicemen who helped in the raid that killed Osama bin Laden a year ago.

With so many troops returning home, Obama says the U.S. needs to return the favour.

“We have to serve them and their families as well as they have served us,” Obama said in his weekly radio and Internet address. “By making sure that they get the health care and benefits they need; by caring for our wounded warriors and supporting our military families; and by giving veterans the chance to go to college, find a good job and enjoy the freedom that they risked everything to protect.”

Veterans could play a significant role in the 2012 election. Exit polls in 2008 showed that Obama was supported by about 44

percent of voters who said they served in the military, while 54 percent voted for Republican John McCain, a former Navy pilot who was a prisoner of war for more than five years during the Vietnam War.

A poll released Monday by Gallup found that 58 percent of veterans support Romney and 34 percent back Obama. The results were based on a sample of 3,327 veterans who are registered voters and had a margin of error of 2 percentage points.

Romney was scheduled to appear Monday with McCain in San Diego. Romney has made the case that too many veterans are returning home to poor job prospects, casting blame on Obama's economic policies.

A Bureau of Labor Statistics report in March found that 12.1 percent of U.S. Armed Forces veterans who served on active duty after September 2001 were unemployed in 2011. The unemployment rate for all veterans was 8.3 percent.

Several closely watched states in the November election have large numbers of military voters. Florida, home to several military installations, has more than 1.6 million veterans, according to the Veterans Administration. Pennsylvania has nearly 1 million veterans, while Virginia and North Carolina each have about 800 000 veterans. - Sapa-AP