The United States is attempting to come to terms with terrible scenes of death and devastation caused by a series of terrorist attacks which destroyed the World Trade Center in New York, and set fire to the Pentagon. President George W Bush told the nation that thousands of lives had been lost.
No one has claimed responsibility for the attacks, in which terrorists crashed two hijacked planes into the World Trade Center, destroying the 110-storey twin towers. A third aircraft was crashed into the Pentagon in Washington DC, causing a massive explosion, and demolishing one side of the building.
A fourth plane travelling from New Jersey to San Francisco crashed about 80 kilometres southeast of Pittsburgh. The four hijacked airliners had 266 people on board, and there are no known survivors.
Addressing the nation from the White House, President George W Bush said thousands of lives had been "suddenly ended by evil, despicable acts of terror". Promising to bring those responsible to justice, Bush added: "We will make no distinction between the terrorists who committed those acts and those who harbour them."
The New York City fire department said more than 300 firefighters were missing. Dozens of police officers are also believed to have died during the rescue effort. In Arlington, Virginia, the fire chief estimates that up to 800 people may have died in the attack on the Pentagon.
US officials reportedly said they had information that the Saudi-born militant, Osama bin Laden, was behind the attacks. They were quoted as saying that they had new information, implicating bin Laden.
Thousands of casualties were expected from the destruction of the twin towers of the World Trade Center, where 50,000 people work.The authorities declared a state of alert throughout the US, and in American embassies and facilities abroad. Public buildings were evacuated and security patrols were deployed around the country's strategic facilities.
Authorities said it could be weeks before the casualty count is known. Many people remained trapped below rubble at the New York and Pentagon disaster sites, some using cell phones to call for help.
All the country's airports were ordered closed, and officials said commercial flights would be grounded until at least midday on Wednesday.
The authorities said five warships had left Norfolk, Virginia, to be deployed protectively along the East Coast of the United States. Two aircraft carriers were being sent to guard the New York City area.
The authorities said shortly after the World Trade Centre disaster, a plane crashed into the Pentagon in Washington DC, setting off a huge explosion and a fire, and prompting an immediate evacuation of major federal buildings. Some 20,000 Pentagon employees were seen streaming into the surrounding car parks.
Emergency measures taken in response to the attacks included the evacuation of US embassies across the world - including in Bern - as well as the suspension of all flights into and within the United States. Swissair and other major carriers were told to divert their planes to Canada.
swissinfo with agencies