The US has for the sixth time vetoed a draft resolution at the United Nations Security Council that would have demanded an immediate and permanent ceasefire in Gaza and the release of hostages.
US deputy Middle East envoy Morgan Ortagus said the text did not go far enough in condemning Hamas or recognise Israel's right to defend itself.
All 14 other members of the Security Council voted in favour of the draft resolution - which described the humanitarian situation in Gaza as catastrophic and called on Israel to lift all aid restrictions.
It comes as the UN's humanitarian office warns that the last lifelines for civilians are collapsing in Gaza City as Israel expands its military offensive.
On the global stage, Israel and its closest ally look increasingly isolated. Speaking prior to the vote, Ortagus said Washington's opposition to the resolution should come as no surprise.
After the vote, UN members reacted swiftly to express their disappointment. Palestinian Ambassador to the UN Riyad Mansour called the US's decision deeply regrettable and painful, while other ambassadors condemned the veto and expressed solidarity with the Palestinian people.
This latest UN vote came just days before world leaders gather for the UN General Assembly, where Gaza is expected to be a major topic.
Meanwhile, Israeli tanks and troops are continuing to advance into Gaza City on the third day of a ground offensive, forcing thousands of people to flee. According to Gaza's health ministry, the escalation has led to significant casualties among civilians.
