United Nations offices around the world have observed a minute of silence for those killed in the 2003 terrorist bombing of the U.N. headquarters in Baghdad.

In New York Friday, U.N. Deputy Secretary-General Louise Frechette laid a wreath in front of the memorial plaque honoring the victims of the August 19 attack. The huge explosion killed 22 people, including the top U.N. envoy in Iraq, Sergio Vieira de Mello, and injured hundreds of others.

In a statement, U.N. Secretary-General Kofi Annan hailed those killed in the bombings, calling them courageous and devoted to helping people in impoverished lands and war-torn countries build better lives.

Mr. Annan withdrew the U.N. international staff from Iraq in October, 2003, following a second attack on its offices in Baghdad and a series of attacks on humanitarian workers throughout Iraq. Since 2004, they have slowly been allowed to return.