CAIRO — The World Health Organization says a diphtheria outbreak in war-torn Yemen has spread rapidly nationwide and infected more than 1,300 people.

WHO said in a statement that children and young adults account for almost 80 percent of cases and more than 70 people have died.

Diphtheria, first reported in Yemen in October last year, is a contagious and potentially fatal disease that primarily infects the throat and airways.

WHO said Friday a vaccination campaign targeting 2.7 million Yemeni children has been completed in 11 governorates.

Yemen has been engulfed in a civil war pitting a Saudi-led coalition backing an internationally recognized government against Iran-backed Shiite rebels since March 2015.

The near three-year stalemated war has damaged Yemen's infrastructure, crippled the health system and pushed it to the brink of famine.