The World Health Organization on Saturday rejected a call for the Rio Olympic Games to be moved or postponed due to the threat posed by a large outbreak of Zika virus in Brazil.

Responding to a call from more than 100 leading scientists, who said it would be unethical for the games to go ahead in August as scheduled, the United Nations health agency said having the games in Rio as planned would "not significantly alter" the spread of Zika, which is linked to serious birth defects.

"Based on the current assessment of Zika virus circulating in almost 60 countries globally and 39 in the Americas, there is no public health justification for postponing or canceling the games," the WHO said in a statement.