Nato says there is no provision for member states to be suspended or expelled from the military alliance after a report said the US could seek to suspend Spain over its Iran war stance.
Reuters quoted a US official who said an internal Pentagon email had suggested measures for the US to punish allies it believed had failed to support its campaign.
The email also suggested reviewing the US position on the UK's claim to the Falklands islands in the south Atlantic, which are also claimed by Argentina.
A Nato official told the BBC that the organisation's founding treaty "does not foresee any provision for suspension of Nato membership, or expulsion".
Spain's leader has also dismissed the report. The BBC has contacted the Pentagon and UK government for comment.
