Speaking under overcast skies after laying a wreath at the Tomb of the Unknowns and meeting privately at the White House with the families of some fallen servicemen and women, Bush called the wars in Iraq and Afghanistan a part of the nation's destiny. He said they follow a rich tradition of similar American sacrifices throughout this country's history.

As people across the country marked the day of remembrance, violence continued in Iraq where a suicide car bomber struck a busy commercial district in central Baghdad, killing at least 21 people and damaging a shrine revered by Sunnis and Shiites alike.

Speaking of the more than 368,000 buried through history at Arlington National Cemetery, Bush said, "Nothing said today will ease your pain. But each of you needs to know our country thanks you and we embrace you and we will never forget the terrible loss you have suffered."

"The greatest memorial to our fallen troops cannot be found in the words we say or the places we gather," he added. "The more lasting tribute is all around us."

Bush said the freedoms that people enjoy in this country today "came at a great cost and they will surive only so long as there are those who are willing to protect them."

The president said that even after four years, many young men and women still volunteer for the U.S. armed forces.

"We've heard of 174 Marines recently, almost a quarter of battalion, who asked to have their enlistments extended," Bush said. "They want to serve their nation."