Nearly 110,000 suspected cases of cholera have been reported in war-hit Yemen since the beginning of January, including 190 related deaths, the UN said on Monday.
The UN office for humanitarian affairs (OCHA) said children under the age of five make up nearly a third of 108,889 cases which were reported between January 1 and March 17.
The OCHA said the spike, which comes two years after Yemen suffered its worst cholera outbreak, was concentrated in six governorates including in the Red Sea port of Hodeida and the Sanaa province home to the capital.
Early rains could be blamed for the recent increase in suspected cholera cases, it said.
"The situation is exacerbated by poor maintenance of sewage disposal systems in many of the affected districts, the use of contaminated water for irrigation, and population movements," OCHA added.
The waterborne disease is endemic to Yemen, which witnessed the worst cholera outbreak in its modern history in 2017.
More than one million suspected cases were reported within an eight-month period that year. More than 2,500 people died of the infection between April and December 2017.
Yemen's brutal conflict, which pits Iran-linked rebels against a regional pro-government alliance led by Saudi Arabia, has left some 10,000 people dead since 2015 and pushed millions to the brink of famine.
The war has created the perfect environment for cholera to thrive, as civilians across the country lack access to clean water and health care.