The administration of US President Joe Biden says Israel's use of US-supplied weapons in the Gaza Strip may have been "inconsistent" with its international humanitarian law obligations, but avoids making a conclusive assessment.

The Biden administration submitted a report to Congress on Friday on Israel's military operations in Gaza between January 2023 and April this year. Assessments and analysis were made based on information from the intelligence communities of Israel and the United States, as well as other sources.

The report also said it was "reasonable to assess" that Israeli security forces used weapons supplied by the US in instances inconsistent "with established best practices for mitigating civilian harm."

But it said, "it is difficult to assess or reach conclusive findings on individual incidents" given the nature of the conflict, and that it will continue to monitor the situation.

Based on an agreement between the two countries, the US would take measures such as reviewing the provision of weapons if violations are confirmed.

Attention has been focused on the US response as Biden has indicated the US would hold off providing ammunition and other weapons if Israel goes ahead with a massive ground operation in the southern Gaza city of Rafah.