UN Secretary General Kofi Annan has said the United Nations was reviewing operations in Iraq after the second deadly bombing at its Baghdad headquarters.
Speaking at UN headquarters in New York, Mr Annan said the organisation needed a secure environment to be able to operate.
A suicide car bomber attacked the UN's Baghdad offices early this morning, killing an Iraqi security guard and wounding 17 people.
A larger bombing there last month killed 22 people, including the top UN envoy in Iraq, and wounded more than 100.
The United Nations pulled many of its staff out of Baghdad in the wake of that attack.
An Iraqi delegation is attending today's UN General Assembly meeting in New York.
The US president, George W Bush, is expected to ask for troops and money from the UN, which he had accused of risking becoming irrelevant in the run-up to the war.
He also said he would tell the Assembly he had no regrets about going to war.
Meanwhile, the French president, Jacques Chirac, said Paris would not veto a UN Security Council resolution on the future of Iraq which is supported by the United States.
However, in an interview in an American newspaper, he repeated that sovereignty should be transferred to Iraq as quickly as possible.
