BERLIN (AP) -- The World Health Organization says there is "no public health justification" for postponing or canceling the Rio Summer Olympics because of the Zika outbreak in Brazil.
The assessment, in a statement early Saturday, came a day after 150 health experts issued an open letter to the U.N. health agency calling for the games to be delayed or relocated "in the name of public health."
Friday's letter cited recent scientific evidence that the Zika virus causessevere birth defects , most notably babies born with abnormally small heads. In adults, it can cause neurological problems, including arare syndrome that can be fatal or result in temporary paralysis.
The authors also noted that despite increased efforts to wipe out the mosquitoes that spread Zika, the number of infections in Rio de Janeiro have gone up rather than down.
The experts came from more than two dozen countries in fields including public health, bioethics and pediatrics, and included former White House science adviser Dr. Philip Rubin.
WHO, however, said "based on current assessment, cancelling or changing the location of the 2016 Olympics will not significantly alter the international spread of Zika virus."
Several public health academics have previously warned that having hundreds of thousands of people travel to the Aug. 5-21 games in Brazil will inevitably lead to the births of more brain-damaged babies and speed up the virus' global spread.
But the Geneva-based U.N. health agency argued that Brazil is just one of dozens of countries reporting the transmission of the Zika virus by mosquitoes and says "people continue to travel between these countries and territories for a variety of reasons."
"Based on the current assessment of the Zika virus circulating in almost 60 countries globally and 39 in the Americas, there is no public health justification for postponing or cancelling the games," it said. "WHO will continue to monitor the situation and update our advice as necessary."
It pointed to its existing advice urging pregnant women not to travel to areas with Zika virus transmission, among other recommendations.
WHO declared the spread of Zika in the Americas to be a global emergency in February.
The agency's statement Saturday made no direct reference to the health experts' letter, which also highlighted the decades-long collaboration between WHO and the International Olympic Committee. The experts called it an "overly close" relationship that left the U.N. health agency unable to be impartial in Olympic matters.
The IOC rejected the idea that the two organizations were too close, saying it "does not currently have an MoU (memorandum of understanding) with the World Health Organization." The last one, it added, "outlined cooperation between the two organizations to promote physical activity to fight strokes, heart attacks, diabetes and obesity."
AP Sports Writer Stephen Wilson and Medical Writer Maria Cheng contributed from London.