UNITED NATIONS, United States (AFP) — President Donald Trump appeared to laugh it off Tuesday when an escalator and a teleprompter both malfunctioned during his United Nations (UN) visit — but for US officials it was no laughing matter.

The White House said an investigation had been launched into whether the moving stairway was stopped on purpose to humiliate the US president, who later bashed the global body in his speech to the UN General Assembly in New York.

“If we find that these were UN and staffers who were purposefully trying to trip up, literally, trip up the President and the First Lady of the United States, well, there better be accountability for those people, and I will personally see to it,” Press Secretary Karoline Leavitt said on Fox News Tuesday evening.

A UN spokesperson said the mishap happened because someone in front of Trump accidentally set off a safety mechanism on the escalator, causing it to shut down.

In a statement earlier in the day, Leavitt pointed to a report in the Times of London newspaper on Sunday saying that UN staff members had joked that they would turn off the escalators and “tell him they ran out of money” amid sweeping US funding cuts.

Footage showed the 79-year-old president and First Lady Melania Trump getting on the escalator at UN headquarters, before it stopped with a lurch after a short distance.