"Meanwhile, the World Health Organization (WHO) is saying that a possible polio outbreak is likely in Syria," he said.
The WHO is waiting for final laboratory confirmation but is treating the situation as a polio outbreak operationally.
"A plan is underway for an emergency response, which would start in the immediately affected area of the Deir es Zour Province," he said.
More than 100,000 people have been reportedly killed since a political crisis broke out in Syria in March 2011. Over two million people have fled the war-torn country and 4.5 million have been internally displaced.