President Donald Trump said on Saturday he may consider rejoining the World Health Organisation, days after ordering a U.S. exit from the global health agency over what he described as a mishandling of the COVID-19 pandemic and other international health crises.

"Maybe we would consider doing it again, I don't know. Maybe we would. They would have to clean it up," Trump said at a rally in Las Vegas.

The U.S. is scheduled to leave the WHO on Jan. 22, 2026. Trump announced the move on Monday after he was sworn in for a second term in the White House.

The U.S. is by far the biggest financial backer of the WHO, contributing around 18% of its overall funding. The WHO's most recent two-year budget, for 2024-2025, was $6.8 billion.

Trump told the crowd in Las Vegas he was unhappy that the U.S. paid more into the WHO than China, which has a much bigger population.

He added that he will ask Saudi Arabia to make an investment of about $1 trillion in the U.S., up from the $600 billion the Saudis have pledged to invest.

Saudi Arabian Crown Prince Mohammed bin Salman told Trump in the past week that the kingdom wants to put $600 billion into expanded investment and trade with the U.S. over the next four years.