The International Olympic Committee said it was investigating a potential breach of Olympic regulations after two cyclists from China wore pins bearing the silhouette of Mao Zedong in a medal ceremony.

The small red and gold pins — once ubiquitous symbols representing Mao’s three-decade rule over China — were attached to the track suits of the cyclists, Bao Shanju and Zhong Tianshi, when they received gold medals in the women’s sprint on Monday.

The cyclists’ badges are a potential violation of Rule 50 of the Olympic charter, which bans “political, religious or racial propaganda” at Olympic venues.

In a news briefing on Wednesday, Mark Adams, an I.O.C. spokesman, said that the committee had asked China’s Olympic delegation to submit a report explaining the incident, and that it had been promised a “full formal answer soon.”

“They have also assured us already that this will not happen again,” Mr. Adams said.

Separately, the Korea Badminton Association said on Wednesday that it had filed a complaint with the World Badminton Federation after a Chinese player was captured on video swearing in a doubles match against South Korean players.

The Chinese badminton player, Chen Qingchen, repeatedly shouted what has been interpreted as a common Chinese obscenity. She apologized, saying that she was merely celebrating points scored and that she would adjust her “bad pronunciation.” But she did not say what she had intended to shout.

The incident was widely reported in South Korea — where nationalists sometimes chafe at China’s assertions of power — but lauded as a spirited and refreshing performance on Chinese social media.

The Chinese team ended up defeating the South Koreans.