British Prime Minister David Cameron and International Olympic Committee President Jacques Rogge have apologized after an image of South Korea's flag appeared ahead of an Olympic women's football match in which the South's rival North Korea was playing.
Rogge downplayed the incident, calling it "unfortunate" and "a simple human mistake."
Cameron said every effort would be made to ensure such a blunder does not happen again during the games.
The North Korean team walked off the field before the July 25 game started after a screen at a stadium in Glasgow, Scotland, displayed South Korea's flag.
The North Korean team later returned to play the match against Colombia, winning 2-0.
The two Koreas remain technically at war following the 1950-53 Korean conflict, which ended in an armistice.
In other women's football matches, Britain, the United States, Japan, Brazil, and Sweden made winning starts against New Zealand, France, Canada, Cameroon, and South Africa.
In another development, triple jumper Voula Papachristou was expelled from Greece's Olympic team over comments she posted on Twitter that were deemed racist.
The Hellenic Olympic Committee said that Papachristou’s posts mocking African immigrants and expressing support for a far-right party went against the Olympic spirit.
Papachristou has apologized for the "unfortunate and tasteless joke."
In comments on July 22, Papachristou referred to the West Nile virus and Africans living in Greece.
She also reposted a tweet by a politician with the far-right Golden Dawn party, criticizing the Greek prime minister's stance on immigration.
The men’s football competition will kick off July 26 when Honduras take on Morocco. The matchups in men's football also include Mexico against South Korea, Spain versus Japan, United Arab Emirates against Uruguay, Gabon versus Switzerland, Belarus against New Zealand, Brazil against Egypt, and Britain versus Senegal.
The official opening ceremony of the games takes place on July 27.
With reporting by Reuters, AP, dpa, and AFP