Typhoid has broken out in an opposition-held region of Syria due to people drinking contaminated water from the Euphrates River, the World Health Organization (WHO) said on Tuesday.

An estimated 2,500 people in northeastern Deir al-Zor province are infected with the contagious disease, which causes diarrhea and can be fatal, the United Nations agency said.

"There is not enough fuel or electricity to run the pumps so people drink water from the Euphrates which is contaminated, probably with sewage," the WHO representative in Syria, Elisabeth Hoff, told Reuters by telephone.

The WHO had no confirmed reports of deaths so far from typhoid.

Typhoid fever is an infection of the intestinal tract and bloodstream caused by salmonella bacteria. People become infected after consuming food or beverages handled by an infected person or by drinking contaminated water.