The UN health agency described a “deteriorating” humanitarian situation in the country, especially in Taez in the centre of the country where there have been heavy clashes.
Fighting and airstrikes by a Saudi-led coalition killed 1,244 people and injured 5,044 between March 19 and April 27, according to the latest WHO toll.
WHO receives its statistics from health facilities in Yemen, but since many people are unable to get to hospitals for treatment the real numbers are probably higher.
The latest toll was published as Saudi-led air strikes entered a sixth week Friday, and did not include the 47 people killed in the latest strikes and clashes on the ground in Yemen’s second city Aden.
The air strikes began in late March when the Iran-backed Huthi rebels and their allies advanced on the main southern city of Aden, where President Abedrabbo Mansour Hadi fled after the rebels seized large parts of the country including Sanaa.
Hadi escaped to Riyadh, which launched its campaign fearing an Iran-friendly regime taking control of its southern neighbour.
In Taez, 19 people were killed and 91 injured on April 26 alone, when the local Al-Thawra hospital was hit, WHO said.
The UN agency also warned Friday that most roads connecting Sanaa to the governorates of Aden, Taez, Al-Dhaale, and Lahj were “becoming gradually inaccessible, making the delivery of life-saving medicines a serious challenge”.
Severe shortages of medicine and health staff were also being reported in areas where the violence was raging, and shortages of safe water were becoming acute across much of the country, it said.
The bombing has virtually halted the delivery of humanitarian aid and other goods, including fuel, with the International Committee of the Red Cross describing the situation as “alarming”.
WHO said disrupted electricity supplies and fuel shortages were being felt across Yemen and were hampering efforts to deliver medical supplies and keep health facilities and ambulances running.
The fuel shortages have also forced the World Food Programme to halt its food distribution in Yemen where most of the stocks are in the hands of rebels.
People seem to be having difficulty accessing health facilities across Yemen, WHO said, and warned of rising numbers of cases of acute respiratory infections, acute diarrhoeal diseases, and malaria.
It also said it had received 44 alerts of suspected disease outbreaks, including measles dengue fever and meningitis.
The International Organization for Migration meanwhile said Friday that more than 12,000 people, both Yemenis and foreign nationals, had fled the country for the Horn of Africa since mid-March, mainly by boat.
More than 8,900 of them had fled into Djibouti and some 3,400 had made it to Somalia. – AFP