In a solemn ceremony, the United Nations has marked the third anniversary of the deadly attacks on the world body's offices in Baghdad.

In a statement Friday, U.N. Secretary-General Kofi Annan said the bombing dealt a fatal blow to the illusion that wearing a U.N. blue helmet or hoisting a U.N. flag placed peacekeepers out of reach of violence.

He said U.N. staff now confront direct and deadly threats to their safety. He said, however, the world body remains committed to work for peace in such places as Lebanon, Darfur, Haiti and Iraq.

Twenty-two people were killed and hundreds others injured when a bomb struck the U.N. offices in the Iraqi capital three years ago Saturday. Among those killed was the U.N.'s top envoy in Iraq and High Commissioner for Human Rights, Sergio Viera de Mello.