The global charity Save the Children is calling for a vaccination ceasefire in Syria to give doctors a chance to inoculate children against polio.
The United Nations says it has confirmed 10 cases of polio in young children in the northeast.
Save the Children says it is necessary to stop the outbreak from turning into an epidemic threatening youngsters across the Middle East. The group says it carried out successful ceasefire vaccination campaigns in Afghanistan, Sudan, and the Democratic Republic of Congo.
U.N. officials say about 500,000 Syrian children have not been vaccinated against polio.
Polio is a highly infectious disease. It can be transmitted through food and water and spreads rapidly among children younger than five. It is incurable and can frequently lead to paralysis or death.
A vaccine created in the early 1950s by the late Dr. Jonas Salk has nearly wiped out polio from the planet. The disease is endemic in only three countries - Afghanistan, Pakistan, and Nigeria. But the World Heath Organization says an epidemic could erupt if just a single child is infected.