Emergency talks have been initiated by the World Health Organization amid rising concern over polio after cases were discovered in Afghanistan, Iraq and Equatorial Guinea.
The UN health agency said that following several days of closed-door discussions, it would decide whether to declare the new spread of polio a "public health emergency of international concern" that could require measures such as travel restrictions.
WHO emergency meetings typically take the form of telephone conferences between experts and officials around the globe, steered from the agency's Geneva headquarters.
The number of recorded cases worldwide has fallen from 350,000 in 1988 to 406 in 2013, according to WHO data.
Polio is currently endemic in three countries, Afghanistan, Nigeria and Pakistan, down from 125 in 1988.
"However, wild poliovirus continues to spread internationally from both endemic and re-infected countries," the WHO said.
"Between January and April 2014, in what is usually the low season for poliovirus transmission, three new international wild poliovirus importation events have been detected, one each in Asia (Pakistan to Afghanistan), the Middle East (Syria to Iraq) and central Africa (Cameroon to Equatorial Guinea)."