LONDON (LA Times) — In an open letter to British Prime Minister David Cameron, published as an advertisement in the Guardian and other newspapers Thursday, the president of Argentina demanded the return of the British-ruled Falkland Islands in the South Atlantic.

In the letter, copied to United Nations Secretary-General Ban Ki-moon, President Cristina Fernandez de Kirchner called for a U.N. resolution to return the Malvinas, as they are known in Argentina, to her country.

“One hundred and eighty years ago on this same date, January 3rd, in a blatant exercise of 19th century colonialism, Argentina was forcibly stripped of the Malvinas Islands,” Fernandez’s letter began.

She further accused Britain of “a population process similar to that applied to other territories under colonial rule,” and demanded that a 1960 U.N. resolution “bringing an end to colonialism in all its forms and manifestations” be put into practice through a negotiated solution to the dispute over the islands.

The British government has either ignored or countered Argentina’s claims with an outright refusal to negotiate, citing the Falkland islanders’ right to self-determination. It has called a referendum for March 10-11 in which the 3,000 or so islanders, most of whom are of British descent, could choose their government.

Giving Cameron’s response Thursday, a spokesperson cited the islanders’ “clear desire to remain British” and endorsed a Foreign Office spokesman’s remarks that “the people of the Falklands are British and have chosen to be so.”

Fernandez’s letter marked the latest attempt by the Argentine government to overturn British authority over the islands. Her government’s recent efforts to force a resolution of the dispute include attempts to ban ships flying the British flag from Argentine waters and to assert Argentine control over oil exploration off Antarctica.

They coincided with the 30th anniversary last year of the short but intense Falklands War, when British forces under then-Prime Minister Margaret Thatcher retook the islands after an Argentine invasion.

Classified government documents on the war were released recently and reveal Thatcher’s surprise at the Argentine invasion on April 2, 1982, discussions of diplomatic solutions in the early stages of the war and her ultimate determination to win the islands back by force despite cautionary advice from President Ronald Reagan and his staff.

According to the documents, they pleaded with her to make a settlement with Argentina’s military dictator, Leopoldo Galtieri, for fear that an escalating war in the region could damage U.S. relations in Latin America.