The head of a UK-based medical charity working in Gaza says the health situation has reached a “catastrophic stage” because of the impossibility of acquiring supplies to treat the hundreds of patients flowing into field clinics.

David Wightwick, CEO of UK-Med, said his team is focusing on the southern city of Khan Younis where the largest proportion of the population is now located.

His aid group set up a field hospital in al-Mawasi and has two others in the south.

About 1,400 victims of war violence in the region seek medical help from UK-Med each day, Wightwick told Al Jazeera. Most of the conflict-related emergencies are blast injuries and gunshot wounds.

But medical supplies have become scarce ever since Israeli forces captured the Rafah border crossing with Egypt last month and began restricting the transport of desperately needed aid.