Oliver Rosenbauer, spokesman for the World Health Organisation's anti-polio division, told reporters that laboratory tests had confirmed the presence of the disease in 10 out of 22 suspected cases reported almost two weeks ago.
All 22 children were stricken with acute flaccid paralysis, which is the symptom of a number of different diseases, including polio.
"Out 10 of those cases, they've isolated wild polio virus type one," Rosenbauer said.
The cases were clustered in the northeastern Deir Al Zour province, and all affected children under the age of two.
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"There are no additional 'hot' cases that we know of. Of course disease surveillance is now ongoing across Syria and neighbouring countries as well, to look for other acute flaccid paralysis cases," said Rosenbauer.
The next step is to analyse the genetic code of the virus to try to track its source.
"This is a communicable disease, and with population movements it can travel to other areas, and so the risk is high of a spread across the region of course," Rosenbauer warned.
The UN says that 500,000 children in Syria have not been vaccinated against polio in the past two years due to insecurity.
Before the Syria conflict, around 95 per cent of all Syrian children were vaccinated.
Rosenbauer said that all the children who have caught the virus in Deir Al Zour appeared to have never been vaccinated against polio, or had not received a full course of vaccine.