A US agency assessed that the Covid pandemic had likely been caused by an unintended Chinese laboratory leak which increased pressure on the World Health body to look into the origins. Finding the origin of Covid is a moral imperative and all hypotheses must be explored, World Health Organization head said, affirming that the UN body is committed to finding how the virus arose, marking his strongest comments yet on the matter. Earlier, a US agency assessed that the Covid pandemic had likely been caused by an unintended Chinese laboratory leak which increased pressure on the World Health body to look into the origins. However, China denied the assessment. "Understanding #COVID19's origins and exploring all hypotheses remains: a scientific imperative, to help us prevent future outbreaks (and) a moral imperative, for the sake of the millions of people who died and those who live with #LongCOVID," said WHO director-general Tedros Adhanom Ghebreyesus on Twitter, marking three years since the world health body first used the word "pandemic" to describe the outbreak of Covid.