The World Health Organization has called for immediate access to Yemen's Taiz city for delivery of life-saving health supplies to more than 250,000 people living in a state of virtual siege since November 2015.

"All of city's six hospitals have been forced to partially close some services, and are overwhelmed with injured patients. Humanitarian organizations are struggling to deliver medical and surgical supplies due to the insecurity," the organization said in a statement Friday.

Since Dec. 14, 2015, five WHO trucks carrying medicines and medical supplies have been prevented from entering the city, it said.

The trucks contained trauma medicines, drugs for treatment of diarrhea, and other health supplies that urgently needed to be delivered to Al-Thawra, Al-Jumhoori, Al-Rawdhaand Al-Mudhaffar Hospitals, it said.

The organization called on all parties involved in the conflict in Taiz to allow the secure movement and delivery of medical and humanitarian aid to all people.

Last month, warring sides in Yemen agreed to a full resumption of humanitarian aid to the city of Taizz during UN-sponsored talks in Switzerland. However, WHO trucks continue to be prevented from entering the city.

According to the UN, more than 2.3 million people have been forced to flee their homes and 21.2 million in Yemen are in need of humanitarian aid.

In September last year, Houthis overran the Yemeni capital, Sanaa, before capturing additional parts of the country, forcing Saudi-backed President Abd Rabbu Mansur Hadi and his government to flee to Riyadh.

In March, Saudi Arabia and its Arab allies began an extensive air campaign aimed at reversing Houthi military gains in Yemen and restoring Hadi’s embattled government.

Hadi has since returned to Yemen’s port city of Aden, which currently serves as the temporary seat of his government, while the Houthis remain in control of Sanaa.

Fighting, meanwhile, continues to rage in several parts of the country between the Houthis and their allies on one hand and Saudi-backed pro-Hadi forces on the other.

According to UN figures, some 6,000 people have been killed since Saudi Arabia and its allies began air-and-ground operations in Yemen almost nine months ago.

Anadolu Agency