Argentina’s government has launched a process to sanction a number of foreign firms it accuses of illegally drilling for oil in a disputed area near the British-run Falkland Islands, over which the South American country also claims sovereignty.

The country’s energy secretary Darío Martínez told reporters on July 7 it would seek sanctions against U.K.-based Chrysaor Holdings, Harbour Energy and Israeli firm Navitas Petroleum, adding them to eight other firms previously sanctioned between 2011 and 2015.

Reuters could not immediately reach the firms for comment.

Argentina and Britain have long disputed ownership of the Falklands, with Argentina claiming sovereignty over the islands it calls the Malvinas. The dispute led to a brief war in 1982 in which 255 British troops and about 650 Argentine soldiers died.

“The companies are not authorized to operate nor have they requested any type of authorization,” Martinez said at a press conference, adding they were operating with illegal licenses from the “illegitimate authorities” of the Falkland Islands.

Argentina’s current center-left Persons government has ratcheted up rhetoric over the disputed islands, some 403.89 miles of the country’s southeast coast and home to some 2,600 people, mostly of British descent.

The government has appointed a Malvinas minister, saying it will redraw maps to emphasize its claim for use in schools and lobbying at the United Nations.