By Michael Buchanan BBC News, Washington

Mark Malloch Brown (left) will discuss UN reform with legislators

The United Nations has taken a major step to try to improve its battered reputation with US lawmakers.

Mark Malloch Brown, the new chief of staff to UN Secretary General Kofi Annan, is to hold meetings with key legislators in Washington.

They are investigating allegations of criminal wrongdoing within the UN's former oil-for-food programme in Iraq.

Last week, an independent inquiry into the operation found evidence of wrongdoing and management failures.

Fraud accusation

This high-profile visit to Capitol Hill represents something of a charm offensive by Mr Malloch Brown.

The Briton is to meet both supporters and opponents of the UN, including holding discussions with a key Republican senator who called for Kofi Annan's resignation last year over the oil-for-food programme.

Senator Norm Coleman accused the secretary general of presiding over the greatest fraud and theft in UN history.

A UN spokeswoman said Mr Malloch Brown was keen to hear ideas on how to reform the world body but would also be emphasising to lawmakers the managerial and administrative changes that are already under way.

These should, the UN says, increase transparency and accountability.