May 18 (Reuters) - U.S. President Donald Trump threatened on Monday to permanently stop funding of the World Health Organization (WHO) and reconsider membership of the United States in the body.

"If the WHO does not commit to major substantive improvements within the next 30 days, I will make my temporary freeze of United States funding to the WHO permanent and reconsider our membership in the organization," Trump told WHO chief Tedros Adhanom Ghebreyesus in a letter posted on Twitter. (Reporting by Rama Venkat in Bengaluru; Editing by Clarence Fernandez)