The British government has called on FIFA to open a formal investigation into Argentina's players after several members of the squad displayed a banner asserting Argentine sovereignty over the Falkland Islands during post-match celebrations following their 2-1 World Cup semifinal victory over England.

The incident occurred Wednesday in Atlanta, where players held up a banner passed to them by fans in the stands. The banner read "Las Malvinas son Argentinas" — meaning "The Malvinas are Argentine" — referring to the disputed archipelago that Britain administers as the Falkland Islands.

Political flashpoint

Argentina has long referred to the Falkland Islands as Islas Malvinas and claims sovereignty over them. In 1982, Argentina's then-military dictatorship ordered an invasion of the islands, sparking a 10-week armed conflict that ended in a British military victory.

A spokesperson for Prime Minister Keir Starmer did not hold back on Thursday. "The World Cup might not be ours, but the Falkland Islands definitely are," the spokesperson said. "Self-determination rests with the islanders and our commitment to the Falklands will never waver."

Starmer's office confirmed the prime minister backed calls for a FIFA investigation, echoing remarks from U.K. Business Secretary Peter Kyle, who described the players' conduct as "entirely inappropriate."

FIFA's disciplinary code in focus

FIFA's disciplinary regulations explicitly ban any messaging at stadiums that is "not appropriate for a sports event," including content of a "political, ideological, religious or offensive nature." Under those rules, the governing body has the authority to sanction both Argentina's players and the Argentine Football Association.

In a statement issued Thursday, FIFA said its independent Disciplinary Committee was already reviewing match reports and assessing the relevant circumstances before determining whether further action was warranted under the FIFA Disciplinary Code.

Should sanctions be applied, fines for political messaging under FIFA's code typically range from around $5,000 to $20,000 — a relatively modest sum for a nation riding high on a World Cup semifinal triumph.