The World Health Organization has set up a Zika “emergency team” after the “explosive” spread of the virus.
Zika virus has been linked to thousands of babies being born with small brains in Brazil.
WHO director general Margaret Chan said Zika had gone “from a mild threat to one of alarming proportions” and was “heart-breaking”.
The team will meet on Monday and decide whether Zika should be treated as a global emergency like Ebola.
Brazil reported the first cases of Zika in South America in May 2015. WHO said estimates suggested 1.5 million people had been infected in the country.
The virus has since spread to more than 20 countries in the region.
Dr Chan said: “The level of concern is high, as is the level of uncertainty, questions abound, we need to get some answers quickly.
“For all these reasons, I have decided to convene an Emergency Committee.
“I am asking the Committee for advice on the appropriate level of international concern and for recommended measures that should be undertaken in affected countries and elsewhere.”
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