Chinese security officers attempted to stop the American military aide carrying the nuclear football from following President Trump into the Great Hall of the People in Beijing in November.

Axios reported Sunday the decision set off a chain of events that led chief of staff John Kelly to intervene and get in a physical altercation with a Chinese security officer.

According to the report, Chinese officials blocked the military aide carrying the nuclear football from following Trump and Chinese President Xi Jinping into the Great Hall. The aide is supposed to be near Trump at all times.

When made aware of the situation, Kelly intervened and told the aide to keep walking and entering the hall. One Chinese official grabbed Kelly and Kelly shoved the man’s hand back. A Secret Service agent then grabbed the Chinese official and tackled him to the ground.

The report indicates Trump’s team properly informed the Chinese about security procedures before the trip. The nuclear football, which contains the codes the president must give to order a nuclear strike, was never in Chinese possession.

The Chinese apologized to the Americans after the incident.