The banner, held up by Lisandro Martinez and Giovani Lo Celso, goes against FIFA’s Stadium Code of Conduct.

Argentina players held up a political banner declaring “Las Malvinas Son Argentinas” (“The Falklands are Argentinian”) after their 2-1 World Cup semifinal victory over England, in apparent contravention of FIFA rules.

FIFA’s Stadium Code of Conduct bans “banners, flags, flyers, apparel and other paraphernalia that are of a political, offensive, and/or discriminatory nature” inside stadiums.

World football’s ruling body did not immediately reply to Al Jazeera’s request for comment on Wednesday.

The question of sovereignty over the islands in the South Atlantic – known to the British as the Falklands and the Argentinians as the Malvinas – has been a long-running sore in relations between the countries.

They fought a short conflict over the islands in 1982, in which 649 Argentinian soldiers and 255 British soldiers died. Britain ultimately won, and the vast majority of the islands’ residents have said they wish to remain part of Britain.

But Argentina has long claimed it inherited the islands from Spain after its independence in 1816 and that Britain took control in 1833 through an illegal colonial act.

Lisandro Martinez and Giovani Lo Celso held up the banner, grinning, and waved to fans in the stands. It was unclear where the banner had come from.

It is not the first time the question of political banners has come up during the World Cup. Last month in Los Angeles, Iranian Americans waved pre-revolutionary flags that are symbols of protest against the Tehran government when Iran played. Those matches proceeded without incident.