Argentine President Cristina Fernandez de Kirchner has claimed that the Falkland Islands serve as a nuclear base for the Nato alliance in the South Atlantic.
Argentina, which calls the archipelago the Malvinas, claims the British overseas possession as its own, and fought a brief but bloody war for it in 1982.
The islands "constitute a Nato military nuclear base in the South Atlantic - this is the truth that they can't continue to hide".
She alleged the archipelago was "among the most militarised areas in the world", saying 1,500 soldiers and 2,000 civilian military personnel were stationed there amid a population of 1,000.
Fernandez claimed the British military managed its entire South Atlantic deployment and its electronic intelligence systems from there.
Britain called the claims "wholly false" and said force numbers had declined to the "minimum necessary to defend the islands".
The Foreign Office said that Britain had "ratified the protocols to the Nuclear Weapons Free Zone covering Latin America and the Caribbean in 1969, and it fully respects these obligations".
Fernandez made the claims during a ceremony honouring the Argentine dead on the 32nd anniversary of the start of the conflict.
Argentine forces invaded the islands on April 2, 1982 but were forced to surrender 74 days later.