The UN Security Council area is being evacuated on Tuesday morning due to "unidentified odor," UN spokesman Farhan Haq told reporters in New York, adding the UN is working with the local authorities to find out the source of the odor.

Staff members of the United Nations wait ouside the UN headquarters in New York, the United States, Dec. 21, 2010. The UN Security Council area is being evacuated on Tuesday morning due to "unidentified odor," UN spokesman Farhan Haq told reporters, adding the UN is working with the local authorities to find out the source of the odor. [Shen Hong/Xinhua]

The United Nations has evacuated all staff and personnel from the General Assembly hall and the UN Security Council due to the " odor," located in the UN complex on Manhattan's east side, Haq said.

The UN is working with New York City authorities to find out the source of the odor, said the spokesman.

The UN security initially said that the odor was from a gas leak in the basement, but this has not yet been confirmed.

A witness to the evacuation said the odor in the main UN complex building was "nauseating" and smelled of "diesel."

A UN security guard said the odor remains unidentified pending investigation.

The evacuation took place just before the scheduled beginning of an informal meeting of the 15-nation UN body "to discuss questions posed to members of the Security Council from young people around the world," UN officials said.

The meeting was later moved to the hall of the Economic and Social Council (ECOSOC), diplomatic sources told Xinhua.

The ECOSOC hall is located in the temporary building on the north lawn of the UN complex, where the UN secretary-general has his office. The temporary building was erected due to the ongoing UN renovations.