He also offered his deepest sympathy to the families and friends of the victims of the disastrous events which centred on the World Trade Centre and the Pentagon on Tuesday.
Mr Toepfer said: "These terrorist attacks in the United States have shocked the world, they have shocked me and they have shocked UN staff here in Kenya. These acts of barbarism occurred on American soil but they were in fact an attack on civilisation, democracy and freedom everywhere".
Our hearts and prayers go out to the innocent victims and families who have suffered from these atrocities. Our thoughts are also with the doctors, nurses, firemen and women and members of the emergency services who have been dealing with the appalling consequences of these attacks. Our prayers are also with George Bush, the US President, and his government," he said.
"Those terrorists responsible must be caught and brought to trial to answer for these crimes against humanity," added Mr Topefer.
He said the attacks in New York and Washington had brought back vivid and heart rending memories of the carnage caused in Nairobi and Dar-es-Salaam on 7 August three years ago. Terrorist bombs were aimed at the US embassies in Kenya and Tanzania killing 224 people and injuring 4,000 more.
"We here in Kenya have direct experience of the misery and grief caused by acts of thoughtless, cowardly, terrorist aggression. In the wake of those attacks in 1998, we at the UN created a Garden of Remembrance and a Peace Pole was erected to serve as a reminder to future generations. But also to
serve as beacons of hope so that soon the world can live as one in peace and harmony, " said Mr Toepfer.
Tomorrow (Thursday) heads and staff of the 23 UN agencies in Kenya and other members of the local and international community will be gathering for a ceremony in the garden which is located in the centre of the UN in Gigiri.
The gathering, which will take place at 10.30am, will show solidarity with the American people and sympathy for the families and victims of the attacks.
For more information please contact Tore J. Brevik, Director of the United Nations Information Centre (UNIC), Nairobi, on Tel: 623292, E-mail: firstname.lastname@example.org or Peter Mwaura, Information officer UNIC, on Tel: 624560, E-mail: email@example.com