October 19, 2013 -- Updated 1730 GMT (0130 HKT)
(CNN) -- The World Health Organization said Saturday it is investigating a possible outbreak of polio in Syria, where an ongoing civil war has decimated the public health infrastructure.
The organization said it received reports Thursday of 'a cluster of acute flaccid paralysis (AFP) cases' in the country. The cluster was detected early in the month, it said, in the eastern province of Deir Ezzor.
'Initial results from the national polio laboratory in Damascus indicate that two of the cases could be positive for polio -- final results are awaited from the regional reference laboratory of the Eastern Mediterranean Region of WHO,' it said.
Wild poliovirus was last reported in Syria in 1999.
Syria's Ministry of Health 'confirms that it is treating this event as a cluster of 'hot' AFP cases, pending final laboratory confirmation,' and is planning an urgent, nationwide response, it said.
Neighboring countries were planning to increase their immunization activities, it added.
