U.S. President George W. Bush says America recommits itself to fighting terrorism, as it remembers the victims of the attacks one year ago on the United States. He spoke at a ceremony in front of the rebuilt walls of the Pentagon.

The president's words were somber, but firm. "One year ago, men and women and children were killed here because they were Americans. And because this place is a symbol to the world of our country's might and resolve," the president said.

He said it is time to pay tribute to those who died that day, and continue the fight triggered by their loss.

"Today we remember each life. We rededicate this proud symbol. And we renew our commitment to win the war that began here," Mr. Bush said.

The president looked out at the crowd and up at the large flag unfurled on this day, cascading down the rebuilt Pentagon walls. It was originally placed by rescue workers over the side of the ruins left behind last September 11 by a hijacked jet that rammed into the building, taking innocent lives.

"The terrorists chose this target hoping to demoralize our country. They failed," he said. "Within minutes, brave men and women were rescuing their comrades. Within hours, in this building, the planning began for a military response."

With the restored walls behind him and an audience of thousands, including the families of the dead, congregated in front, the president sent a message of bittersweet remembrance mixed with resolve. He said the murder of innocent people cannot be explained, only endured, and though they died in tragedy, they did not die in vain.

"What happened to our nation on a September day set in motion the first great struggle of a new century. The enemies who struck us are determined and resourceful. They may not be stopped by a sense of decency or a hint of conscience. But they will be stopped," the president warned.

The Pentagon was the first stop on a day-long journey by the president to the three sites where hijacked planes crashed on September 11, 2001.

He went directly from the massive defense department building and its crowd of military personnel and dignitaries, to a quiet field near Pittsburgh, Pennsylvania. It was there, in the tiny town of Shanksville, that a commandeered jet on a path to Washington slammed into the ground, after passengers took on the hijackers.

The president planned silent tributes, the simple laying of memorial wreaths, in both Shanksville and the eerie open expanse in New York called "Ground Zero" where the World Trade Center towers once stood.

He will make only one other speech to mark the passing of one year since the terrorist attacks, a brief address broadcast to the nation in the evening from New York's Ellis Island, where generations of immigrants got their first glimpse of the United States.