Britain spied for several years on the Argentine government over fears of a fresh attempt to retake the Falkland Islands, documents released by American whistle-blower Edward Snowden have claimed.
Snowden said British agents were actively spying on Argentina between 2006 and 2011.
Britain was concerned that Argentina could launch another attempt to reclaim the Falkland Islands, according to reports.
The two nations fought a war over the islands in 1982.
The former CIA worker, who now lives in Russia, has previously leaked sensitive information about United States surveillance programmes. He is now fugitive from his native country after leaking the sensitive information.
There has not been any formal response yet from either the British or Argentine government to the allegations, which have been published by a number of South American news agencies.
The claims are that Britain began a large scale operation which may have involved implanting computer viruses, circulating false propaganda and collecting intelligence with the aim of diminishing or discrediting the Argentine government.
The news comes around the 33rd anniversary of the start of the war, which saw more than 900 servicemen killed.
UK defence secretary Michael Fallon said last month that Britain will spend 280 million pounds over the next 10 years on renewing and beefing up its defences of the Falkland Islands, to taking into account any future and possible threats to the islands.