Israeli forces opened fire on crowds of Palestinians seeking aid in Gaza City, killing six people and wounding at least 83 others, according to media reports.
Separately, UNRWA said an Israeli strike had hit one of its warehouses in the southern city of Rafah, killing an employee.
The attacks come as donor nations, aid agencies and charities are pushing on with efforts to rush food to the territory of 2.4 million people, where famine looms after more than five months of war and Israeli-imposed siege.
Mediation efforts have so far failed to secure a new truce, and Israeli Defence Minister Yoav Gallant vowed again that Israeli forces "will reach every location" in Gaza.
Israeli forces have carried out a relentless campaign of air strikes and ground operations in Gaza, killing over 31,000 Palestinians, most of them civilians.