The Biden administration has warned Israel that it must increase the amount of humanitarian aid it is allowing into Gaza within the next 30 days or it could risk losing access to U.S. weapons funding.

Secretary of State Antony Blinken and Defense Secretary Lloyd Austin warned their Israeli counterparts in a letter dated Sunday that the changes must occur. The letter, which restates U.S. policy toward humanitarian aid and arms transfers, was sent amid deteriorating conditions in northern Gaza and an Israeli airstrike on a hospital tent site in central Gaza that killed at least four people and burned others.