Renewed fighting between the Iran-backed Houthis and Saudi-backed government forces has killed 838 people and wounded more than 3,000 in Yemen since early August, the World Health Organization said. Tens of thousands have been displaced since clashes resumed after four years of relative peace.

The renewed war is worsening an existing humanitarian crisis. Trauma cases are displacing maternal health patients in hospitals, while families forced from their homes face cholera risks as they struggle to find clean water. More than 120,000 Yemenis were displaced within three weeks, according to the United Nations.

The Houthis seized Yemen’s Red Sea coast this month and have since pushed inland. Their offensive followed rising tensions with Saudi Arabia, including a Houthi blockade on Saudi shipping and missile and drone attacks into the kingdom.

The figures do not distinguish between civilians and combatants. Aid agencies warn the crisis is deepening with each day of fighting.