Downing Street has said the sovereignty of the Falkland Islands 'rests with the UK', following a report the US could review its position on the British claim to the territory. The same internal Pentagon email, which was first reported by Reuters, suggested measures the US could pursue in retaliation against allies it believed had failed to support its campaign in Iran. Asked about the report, a No 10 spokesman said: 'The Falkland Islands have hugely voted overwhelmingly in favour of remaining a UK overseas territory, and we've always stood behind the islanders' right to self-determination and the fact that sovereignty rests with the UK.' BBC News has not seen the Pentagon email. The prime minister's official spokesman also emphasized that the government 'could not be clearer about the UK's position', asserting that 'sovereignty rests with the UK and the islanders' right to self-determination is paramount'. He continued: 'We've expressed this position previously clearly and consistently to successive US administrations and nothing is going to change that.' BBC News has contacted the Pentagon about the reported email. The Falkland Islands review was one of a number of measures suggested in the email, which also included suspending Spain from NATO due to its opposition to the Iran war. A NATO official stated that the organization's founding treaty 'does not foresee any provision for suspension of NATO membership, or expulsion'. Earlier, Spain's Prime Minister Pedro Sanchez commented: 'We do not work based on emails. We work with official documents and official positions taken, in this case, by the government of the United States.' The Falkland Islands, a British overseas territory in the south-west Atlantic Ocean, remain a subject of dispute between Britain and Argentina, which continues to claim sovereignty over the islands, known as the Malvinas. A conflict in 1982 sparked by Argentina's military invasion ended with UK forces recapturing the islands after a 10-week war.