The United Nations may suspend food assistance to areas controlled by Houthi rebel forces in Yemen, the World Food Programme (WFP) announced in a statement earlier this week.

"We face daily challenges due to the unrelenting fighting and insecurity in Yemen,” WFP said in the statement. “And yet, our greatest challenge does not come from the guns, that are yet to fall silent in this conflict — instead, it is the obstructive and uncooperative role of some of the Houthi leaders in areas under their control." 

The consideration to suspend assistance comes after discovering that aid, intended for Yemen’s needy population, is being diverted to support rebel forces.

Last year, the UN found that an estimated 1% of food and supplies being sent to Yemen had gone missing, CNN reported. 

Documents were forged to indicate that the aid had been received by beneficiaries, but supplies were, instead, sold in local markets and food was redirected to others without WFP authorization, leaving thousands of civilians in the Houthi-controlled city of Sanaa starving.

There was also evidence that food aid had been removed from distribution centers and that Yemeni officials had tampered with records indicating those selected to receive aid, WFP said in December, according to Al Jazeera.

In response to these discoveries, WFP called on Houthi leaders to allow the organization to conduct “an independent selection of beneficiaries” and to implement a biometric registration system. Houthi leaders agreed to both and after this first call for collaboration, there was some progress, said Herve Verhoosel, a WFP spokesman.

But Verhoosel admitted that there have been major setbacks in the past several weeks, Al Jazeera reported. 

In March, diplomats and members of humanitarian organizations said that most of the aid in Saada, another city under Houthi control, was being used as political bribes to gain support, according to CNN. 

Read More:85,000 Children Have Died From Hunger in Yemen: Report

David Beasley, head of WFP, estimates 5% to 10% of the organization’s aid is now missing. However, WFP is unsure of exactly how much aid has been stolen because there was no active monitoring system, due to a lack of cooperation from some individuals within Houthi leadership, he added.

"Unfortunately, [Houthi leaders] are being let down by other Houthi leaders who have broken assurances they gave us on stopping food diversions and finally agreeing to a beneficiary identification and biometric registration exercise,” WFP said in this week’s statement. 

The statement also detailed the various other obstacles the organization has had to fight against to deliver aid. 

"Humanitarian workers in Yemen are being denied access to the hungry, aid convoys have been blocked, and local authorities have interfered with food distribution," the statement read. 

These challenges are preventing assistance from reaching the 12 million Yemenis WFP planned to feed this year.

Read More:18 Million Yemenis Could Face Starvation by the End of the Year, UN Says

The WFP statement went on to declare that the organization would partially suspend aid to the Houthi-controlled areas, as a last resort, unless given access to those in need of assistance and the ability to decide who should receive aid without interference. 

Hussin Al-Ezzi, the deputy foreign minister of the Houthi government denied the allegations of theft and tampering in a statement to CNN. 

"Mistakes happen sometimes, but this doesn't mean or doesn't represent a policy on our side,” he said. “We are happy with whatever aid reaches citizens, because these citizens are our strength and support.”

According to the World Health Organization, tens of thousands have died in Yemen since the start of the conflict in 2015. 

To reduce risk of further harm by the suspension of aid, WFP said they would continue any nutrition initiatives that directly target women and children suffering from malnutrition.