Houthi health ministry in Yemen stated on Tuesday that 121 people had died of swine flu (H1N1) throughout the last four months.
"590 people are infected with H1N1 in several Yemeni governorates, including Sana'a, Hodeida, Sa'ada and Dhale," said the rebel-run ministry in a statement.
"Despite actions taken by health authorities, the epidemic is still spreading," added the statement.
Houthi ministry called upon WHO, UNICEF and other world health groups to immediately respond to the viral infection and other epidemics that have occurred during the 4 years of war in Yemen.
On 17 January, Houthi spokesman Dr. Yusuf al-Hadheri accused international groups, mainly the World Health Organization, of causing such diseases to occur and of failing to do their duties in tackling the epidemic spread since three months.
"Only promises the patients have received from the WHO," the statement said accusing the organization of being "very slow in taking actions, though Sana'a Airport is open for organizations."
The war-torn Yemen has been divided between the Iranian-backed Houthis and the internationally recognized government since late 2014.
On 23 January, the WHO warned of health system's looming collapse in the impoverished Yemen as a result of the 4-year war.
At time, WHO tweeted that Yemen's health system witnessed severe shortage in basic medicines and medical supplies, noting that it continued, with WB generous aid, supporting government hospitals across Yemen.
Mid-January, the organization said 45 percent of Yemen's health facilities were out of service, because of war, and that 22 million Yemenis were in desperate need for food.
The largest part of Yemen's health infrastructure has collapsed amid acute shortage of medical supplies, low rates of vaccination and unpaid health care staff.
UN and other humanitarian and relief groups recently warned that millions of Yemenis facing the world's worst starvation, with some 20 million people on the brink of a conflict-resultant famine.
The war has also pushed the country to the world's worst humanitarian crisis, according to the UN, with more than 22 million people in need for a type of humanitarian aid and immediate protection, including 8.4 million people unsure how to get next meal, and some 2 million children suffering severe shortage of nutrition.