John Kelly, the White House chief of staff, "got into a physical altercation" with a Chinese official during President Donald Trump's visit to Beijing last year, The Wall Street Journal reported.

Kelly reportedly told colleagues he would not accept an apology from the official unless it occurred under a US flag in Washington, DC.

Relations between Washington and Beijing are tense as Trump spars with the Chinese government over trade and other issues.

John Kelly, the White House chief of staff, "got into a physical altercation" with a Chinese official during President Donald Trump's visit to Beijing last year and refused to accept an apology, The Wall Street Journal reported on Friday.

The official was reportedly attempting to access the nuclear football, a 45-pound aluminum briefcase that's always by the president's side, carried by a military aide. It contains information and instructions for the president on how to conduct a nuclear strike.

Kelly told colleagues he would not accept an apology from the official unless it occurred under a US flag in Washington, DC, according to the report.

The White House did not immediately respond to a request for comment from Business Insider.

The news website Axios reported earlier this year that a Secret Service member tackled a Chinese security official after the military aide carrying the football was blocked from following the president into a room.

Kelly reportedly intervened, the Chinese official grabbed him, and Secret Service tackled the official.

The official never actually touched the football, and the head of Chinese security apologized, according to the Axios report. But it seems Kelly may not have accepted.

Relations between Washington and Beijing are tense as Trump spars with the Chinese government over trade and other issues. The US intelligence community has also repeatedly warned of China's efforts to steal US trade and technology secrets, and Trump has accused China of working to interfere in US elections.

Many of the president's top advisers have expressed deeply skeptical views of the Chinese government, though Trump has publicly praised Chinese President Xi Jinping.