WASHINGTON — On the fourth anniversary of the Sept. 11 terrorist attacks, in which nearly 3,000 people died, the nation's commemorations will be as varied as its geography.

In Oregon, a 9/11 Memorial Tapestry will be displayed at the Corvallis Arts Center and a song inspired by the images of that day will be performed. A national grass-roots nonprofit called One Day's Pay urges people to observe the day with acts of charity.

In the nation's capital, a government agency that has often been the target of protests is sponsoring a march. The Pentagon's "America Supports You Freedom Walk" is intended to honor the U.S. military and the victims of the terrorist attacks, but critics say the administration is using the occasion to try to stiffen U.S. resolve in Iraq and to counter a major anti-war protest in Washington two weeks later.

Defense Secretary Donald Rumsfeld announced the Pentagon march last month, as an occasion "to remember the victims of Sept. 11, 2001, to honor U.S. troops and veterans and to highlight the value of freedom."

The 1.7-mile walk from the Pentagon to the National Mall will be capped by a concert featuring country star Clint Black, who in 2003 recorded the pro-military song "Iraq and Roll."

The march also will showcase the drive to build a memorial to the 184 victims who died when American Airlines Flight 77 crashed into the Pentagon.

But critics deride the event as a scheme by the Pentagon to brand the Sept. 11 attacks as the precursor to a necessary war. Only those who had registered by Friday will be allowed to march — the Pentagon expects up to 10,000 to participate — and officials are blocking access to the march route with 4-foot-high snow fencing, presumably to keep protesters at a distance.

"This is a desperate propaganda ploy, an attempt to link Sept. 11 to the war in Iraq," said Adam Eidinger, a coordinator for Operation Ceasefire, one of the sponsors of anti-war protests scheduled in Washington on Sept. 24, which organizers forecast could attract 100,000 participants.

Some families of those who died in the attacks were outraged that the Pentagon paired the anniversary with a tribute to the military.

"How about telling Mr. Rumsfeld to leave the memories of Sept. 11 victims to the families?" said Monica Gabrielle, who lost her husband in the World Trade Center. ""Instead of a Freedom Walk, how about a Truth Walk? I think it's about time."

But those who defend the event see nothing wrong with walking to support U.S. troops on a day that marks a deadly terrorist attack on American soil.

"Some of the critics are seeing a connection where none is intended," said Victoria Clarke, a former Pentagon spokeswoman who is taking her children to the march. "People are perfectly within their rights to oppose the policy of war, but this is about supporting the troops."

Officials at the Pentagon had trouble containing their fury at the criticism.

"Those critics weren't sitting here in this building when I was and 184 of my colleagues were killed," said spokesman Bryan Whitman, referring to the people on Flight 77 and those on the ground. "I can appreciate that Americans all across the country will decide what is the most appropriate way to remember this day. We feel this is the appropriate and fitting way to remember those who died right here in this building and also to bring awareness to future site of the memorial."

The Pentagon Memorial will have 184 benches, lit from below, each dedicated to a victim along a timeline of their ages, from 3-year-old Dana Falkenberg to John Yamnicky, 71.

"This is the only attack where children died," said Jim Laychak, who heads the Pentagon Memorial Project. "It's a powerful way of representing the tragedy, to make people think but not tell them what to think."

Laychak, whose brother David was among those killed at the Pentagon, hopes to break ground for the memorial in fall 2006. The project has raised almost $9 million of $18 million needed to build the memorial.