Four years after the September 11 attacks, the United States briefly shifted focus yesterday from its latest disaster - Hurricane Katrina - to memorials for victims of the hijacked-plane strikes in New York, Washington and Pennsylvania.

In Washington, President George W. Bush and most of his cabinet observed a moment of silence to mark the anniversary of the attacks that claimed more than 2,700 lives.

Defence Secretary Donald Rumsfeld, who laid a wreath at Arlington National Cemetery, sounded a somber note.

"I wish we could say ... that this is a time for peaceful remembrance, that we were gathering today to commemorate a danger that had long since past," Rumsfeld said. "... But we cannot. The enemy, though seriously weakened and continuously under pressure, continues to plot attacks and the danger they pose to the free world is real and present."

At Ground Zero in New York City, brothers and sisters of the thousands killed in the collapse of the World Trade Center tower read out the victims' names to a hushed crowd of several hundred.

"Again, we are a city that meets in sadness," Mayor Michael Bloomberg said. "We are all linked to one another in our common humanity."

Former New York Mayor Rudolph Giuliani, praised as a unifying leader after the attacks, told the group, "All of you here today who lost a sister or brother should know their loved one helped to save the spirit of our nation on the day of our greatest attack."

Outside the Pentagon - where a hijacked airliner killed 184 - thousands of marchers stepped off at mid-morning on a commemorative Freedom Walk to the US capital's central Mall, where an afternoon concert was scheduled.

At the White House, a US Marine Corps bugler played "Taps" at 8:46 AM EDT (12:46 GMT), the moment that a hijacked airliner slammed into the north tower at the World Trade Center four years earlier.

Bush and first lady Laura Bush, flanked by Vice-President Dick Cheney and his wife Lynne, stood silently on the South Lawn of the White House for a few moments, just long enough for the song to end.

Most of the Bush cabinet, including Rumsfeld and Homeland Security Secretary Michael Chertoff, looked on under clear blue skies much like those over Washington and New York on the late summer morning in 2001.

Earlier, the Bushes attended St. John's Episcopal Church near the White House, where they lit a candle in memory of the September 11 victims.

Bush was to depart later on Sunday (local time) for his third trip to the hurricane-hit Gulf Coast region. The Bush administration has come under fire from critics as being slow to respond to Hurricane Katrina.

(China Daily September 12, 2005)