The World Health Organization (WHO) on Thursday voiced deep concern over increasing cases of measles and rubella among children in war-torn Yemen after its immunization work faced a funding shortage.

As of July 31, the number of suspected cases of measles and rubella in Yemen has reached almost 34,300, and there were 413 deaths, compared to 27,000 cases and 220 associated deaths in 2022, WHO said in a press release.

It also said "there is limited information on the outbreak's impact on pregnant women who remain at high risk."

"Ideally, the outbreak response vaccination campaign should target at least all children under the age of 10 to be comprehensive and effective; however, the current funding gap has eroded support and limited the target to children under five years of age, the group with higher mortality rates," Arturo Pesigan, WHO Representative in Yemen, was quoted as saying in the press release.

The recent statements of WHO and United Nations Children's Fund (UNICEF) estimated the number of children in Yemen at 12.9 million out of the entire population of 23.4 million.

According to the WHO-UNICEF National Immunization Coverage Estimate for 2022, 27 percent of children under one year of age in Yemen are unvaccinated for measles and rubella and have not met the minimal set of vaccines for full protection.

The collapse of the economic and health systems in Yemen due to the conflict, as well as the overcrowded living conditions in displacement camps contributed to the increased rates of the cases, according to the WHO.

WHO added in the press release that it plans in September to carry out a measles-rubella vaccination campaign, targeting 1.2 million children under the age of five.

Yemen has been mired in a civil war since late 2014 when the Iran-backed Houthi militia took over several northern provinces and forced the Saudi-backed Yemeni government out of the capital Sanaa.

The war has killed tens of thousands of people, displaced 4 million, and left millions of children in urgent need of humanitarian assistance and protection.