US: Four years after the September 11th attacks, the United States briefly shifted its 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, which claimed more than 2,700 lives.
At "Ground Zero" in New York city, brothers and sisters of the thousands of people killed in the collapse of the World Trade Centre towers 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, who was praised as a unifying leader after the 2001 attacks, told the group: "All of you here today who lost a sister or brother should know that 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 people - thousands of marchers took part in a commemorative "Freedom Walk" to the US capital's central mall to attend a concert.
At the White House, a US Marine Corps bugler played Taps at 8.46 am, the moment a hijacked airliner slammed into the north tower of the World Trade Centre four years previously. President Bush and first lady Laura Bush, flanked by Vice-President Dick Cheney and his wife, Lynne, stood silently on the south lawn as the song was played.
Earlier, the Bushes attended St John's Episcopal Church, near the White House, where they lit a candle in memory of the September 11th victims.
Mr Bush departed later yesterday on his third trip to the hurricane-hit gulf coast region. His administration has come under fire from critics for being slow to respond to Hurricane Katrina, which devastated New Orleans and left thousands homeless and unknown numbers dead.