How do UN vehicles serve Houthis in the battlefields?

Witnesses in Marib (Northeast Yemen), said on Tuesday they saw ambulance vehicles (2020 models), which the Iran-backed Houthis sent to battlefields in the same Governorate.
Self-sterilized ambulance vehicles equipped with the highest international medical specifications were sent by the UN World Health Organization to the Houthis to contributing to efforts to combat the outbreak of the Coronavirus, but the Houthis looted, seized them, and sent them to the battlefields to use them. Informed sources confirmed to Khabar Agency
The Iran-backed Houthi militia pushed these vehicles to the frontlines to aid their elements, not concerned with the lives of people and the pandemic. Other identical sources said.
The sources indicated that the militia, which received significant aid from the WHO, including coronavirus tests and a number of drugs, masks, and sterilizers, was diverted by the Houthis to Hezbollah in Lebanon.