By Eric Johnson
CHICAGO (Reuters) - Americans paused in somber reflection on Monday to honor the men and women of the armed services who died fighting the nations' wars -- and to show solidarity for the thousands more now in campaigns overseas.
Across the nation people laid flowers and wreaths upon soldiers' graves, marched in parades, and hoisted flags on the federal holiday, whose origin dates back to the Civil War era.
President Barack Obama marked the occasion by laying a wreath on the Tomb of the Unknowns at Arlington National Cemetery.
"This day is about you and the fallen heroes you loved. It is their courage, their unselfishness, their devotion to duty that has sustained this country through all its trials and will sustain us through all our trials to come," Obama said.
"To those of you who mourn the loss of a loved one today, my heart breaks, goes out to you. I love my daughters more than anything in the world, and I cannot imagine losing them. I can't imagine losing a sister or brother or parent at war," Obama told the families of veterans and television audience.
"The grief so many of you carry in your hearts is a grief I cannot fully know," Obama said. "It's a day that has a meaning for all Americans."
Rick Witek, a 60-year-old truck driver in the town of Withee, Wisconsin, attended a memorial service with his family at a local cemetery where his brother, Sergeant Edward Witek, was buried.
Sergeant Witek was killed in action during the Vietnam War in 1970.
"When you do join the military, you are signing up to risk your life for your country," said Witek. "It is a great feeling to know that people are coming alive to support our soldiers."
The weight of those memories was eased, Witek said, by the return of his son Joshua, 24, of the Wisconsin National Guard, who came home in April after serving in northern Iraq.
"I am thankful for his return, but also thankful that he volunteered to serve his country," Witek said. "He served to prevent more terrorist attacks -- and to let people know terrorists won't get away with it."
Memorial Day came as the Obama administration faces mounting pressure for a complete troop withdrawal from Iraq, where more than 4,400 American service members have died since the U.S.-led invasion in March 2003, and a troop drawdown in Afghanistan, where more than 1,500 American service members have died since 2001.
Prior to the Arlington ceremony, Obama nominated Army General Martin Dempsey, who commanded troops in the Iraq war, as the top U.S. military officer. If confirmed by the Senate, Dempsey would replace Admiral Mike Mullen as chairman of the Joint Chiefs of Staff when he steps down on October 1.
(Additional reporting by Mary Wisniewski. Editing by Peter Bohan)