Brazil sends one swimmer home and warns another after they left athletes' village

The two swimmers had left the village, where most athletes for the Paris Games are staying, without their team's knowledge and their infraction was discovered following their posts on social media.

The BOC said in a statement it had received a communique on Saturday from the head of the country's swimming team informing them the swimmers had "committed acts of indiscipline".

The BOC said it had decided to punish the athletes but Vieira then also challenged the relay team formation.

"The athlete Ana Carolina, in a disrespectful and aggressive manner, contested a technical decision made by the Brazilian National Swimming Team committee," it said.

"As a result, Gabriel Santos was given a warning and Ana Carolina Vieira was dismissed from the delegation. She will return to Brazil immediately."

The 22-year-old Vieira competed on Saturday with the 4x100 metres freestyle relay team that finished 12th in the heats.

"We're not here playing or taking a vacation," said Gustavo Otsuka, Brazil's swimming team leader. "We're here working for Brazil, for the 200 million taxpayers who are working for us."

"We can't play around here. She took a completely inappropriate position to make her point, her dismay, about the formation of the relay."

"It was during this period that we decided to take this situation to the disciplinary committee, discussed it and took the appropriate action. We ended up finding out through the posts," he said.