The 40 passengers and crew who died when hijacked United Airlines Flight 93 crashed into a field were honored as "citizen soldiers" on the sixth anniversary of their deaths in the Sept. 11 terrorist attacks.

After the Pledge of Allegiance and a moment of silence, four surviving family members read the name of each victim — as two bells were rung after each — at the temporary memorial erected near the abandoned strip mine where the plane crashed.

Homeland Security Secretary Michael Chertoff made an unannounced visit to the 30-minute ceremony.

Chertoff said he had three messages for the 300 or so family members, first responders and spectators who stood in a light rain: the abiding love the families have for the victims, the inspiration derived from their heroism, and the nation's rededication to prevent future attacks.

"You have my admiration, you have my love and you have my promise that we will continue to work every single day to protect the people of this country, all in the name of those who perished heroically on Flight 93 six years ago," Chertoff said.

Chertoff echoed Gov. Ed Rendell's comments that the passengers and crew were "citizen soldiers" in the war on terror. Rendell also pledged to support efforts for a permanent memorial at the site.

"It is important that this memorial become a reality," Rendell said. "We will make this happen."

Flight 93, which was en route from Newark, N.J., to San Francisco, was the only one of the four planes hijacked that day that did not reach its intended target, believed to be in Washington, D.C. Investigators believe the hijackers crashed the plane into a field near Shanksville, about 65 miles southeast of Pittsburgh, as passengers rushed the cockpit.

"As American citizens we're all looking at our heroes," said Kay Roy, whose sister Colleen Fraser, of Elizabeth, N.J., died in the crash. "These are our heroes and I'm glad that one of my family members happens to be one of these heroes."

Sgt. Bob Witte, a New York City traffic police officer, said he was sick in bed that morning and went to work after two planes crashed into the World Trade Center towers. He said he has visited the Pentagon, which was hit by another hijacked jet, and decided to mark the sixth anniversary of the attacks at the Flight 93 site.

"I figured, I'd been to the Pentagon and I'd come out here and take some time to reflect," Witte said.

Visitors parked in a muddy field and walked up a small path to the temporary crash memorial site, which is marked with, among other things, small metallic red, white and blue angels — one for each of the 40 crash victims.

A chain-link fence, laced with small flags, signs and other mementos marks the site, along with a wooden cross and the two bells rung during the ceremony.

Plans for a $58 million permanent memorial are ongoing, but have been marked by controversy because the winning park design originally was crescent-shaped. The designer changed it to a nearly full circle in response to critics who said the original shape honored the Muslim extremists who carried out the attacks. The crescent is a Muslim symbol.

The father of one of the passengers wants his son's name withheld from a memorial because he believes the design is still rife with Islamic symbolism.

Construction on the permanent memorial and national park is scheduled to begin by 2009, but fundraising has fallen well short of organizers' goals.