The US is waging a secret "dirty tricks" campaign targeting UN Security Council delegations in New York in its battle to win votes in favour of war against Iraq, the Observer reported Sunday.

The British weekly said it had obtained a document providing details of a surveillance operation which involves interception of the home and office telephones and the e-mails of UN delegates.

The paper said the disclosures were made in a memorandum written by a top official at the National Security Agency (NSA), the US body which intercepts communications around the world, and circulated to senior agents in his organisation and to a friendly foreign intelligence agency.

The memo describes orders to staff at the agency to step up surveillance "particularly directed at... UN Security Council members" to provide up-to-the-minute intelligence on the voting intentions of

UN members regarding the issue of Iraq.

The leaked memorandum, dated January 31, makes clear that the target of the heightened surveillance efforts are the delegations from Angola, Cameroon, Chile, Mexico, Guinea and Pakistan at the UN headquarters in New York, according to the British weekly.

Along with Spain and the United States, Britain has sponsored a new UN resolution declaring Iraq in non-compliance with earlier Un demands that it disarm, which would in effect authorise the use of force against the Baghdad regime.

The resolution needs nine votes to pass while avoiding a veto by any of the five permanent members, and Britain and the US are lobbying feverishly for support.

The votes of the so-called 'middle six' delegations are being fought over by the pro-war party, led by the US and Britain, and the party arguing for more time for UN inspections in Iraq, led by France, China and Russia.