Chinese former leader Hu Jintao has been led out of the closing ceremony of the Communist Party Congress.
The frail-looking 79-year-old was sitting beside President Xi Jinping when he was escorted away by officials.
There has been no official statement by the Chinese government concerning the incident, but state news agency Xinhua said Mr Hu had not been feeling well.
After the week-long congress, the party is expected to confirm Mr Xi, 69, for a historic third term.
The event, held in Beijing every five years, cemented his position as China’s most powerful leader since Mao Zedong.
Hu Jintao, who held the presidency between 2003 and 2013, was on stage when two officials approached him. He said something to Xi Jinping, who nodded back.
Then Mr Hu was escorted out of the Great Hall of the People.
The footage of Mr Hu being asked to leave the stage is drawing global attention as people try to work out what happened, says the BBC’s China correspondent, Stephen McDonell.
He adds that so far, there are a lot of questions and no answers from the Chinese government.
Chinese state news site Xinhua reported that Mr Hu had not been feeling well during the session. It said his staff then accompanied him from the session to rest, adding that he is “much better” now.
Earlier on Saturday, the Central Committee of 205 senior party officials was elected. Delegates rubber-stamped amendments to the party’s constitution endorsing Mr Xi’s ideas as guiding principles for China’s future.
In his opening speech at the Congress last Sunday, he hailed the crushing of the pro-democracy movement in Hong Kong as a move from “chaos to governance”. He also reaffirmed China’s right to use force to seize the self-ruled island of Taiwan.
Mr Xi currently combines the positions of general secretary of the Communist Party, president and head of the armed forces. He is also referred to as Paramount or Supreme leader.
On Sunday he is expected to be officially confirmed for a third term as general secretary and to unveil his new leadership team.
In 2018, he abolished the presidential two-term limit, paving the way for him to rule indefinitely.
