Syria's Minister of Health Saad al-Nayef said Sunday that a recent campaign of the polio vaccination has covered more than two million Syrian children, according to the state-run SANA news agency.

The campaign reached to 2,492,821 children, al-Nayef said, adding that the latest statistics don't include the vaccinated children in the country's northern city of al-Raqqa, which has been captured by the radical rebels from the Islamic State of the Iraq and the Levant (ISIL).

The minister said that the second national campaign faced difficulties due to the armed rebels' attacks on the vaccinations' convoys and medical staffs in some areas.

The minister placed the number of the polio-infected kids at 17, of whom 15 cases were reported in al-Mayadin area in the eastern province of Deir al-Zour, one in the northern province of Aleppo and one in Damascus countryside.

14 cases out of the 17 are children under two years old while the others are under five, the minister said.

The World Health Organization (WHO) said recently that the recent polio outbreak in Syria is the first since 1999, adding that the preliminary evidence indicates that the poliovirus is of Pakistani origin and is similar to the strain detected in Egypt, the West Bank and Gaza Strip over the last 12 months.