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The US has reportedly barred a weapons transfer to Israel for the first time since October 7, a move that comes as President Joe Biden faces continued anger for his administration's support to Israel.
Axios on Sunday cited two Israeli sources as saying that Washington last week put an ammunition shipment on hold.
Members of Mr Biden's own Democratic Party have repeatedly written to him to express concern over how Israel is using US-made weapons in the Gaza Strip, where about 35,000 people have been killed, according to health authorities.
Some politicians also say the State Department is breaking US requirements for military aid to be used under international law.
The White House did not comment on the Axios report, which caused a flurry of outrage in conservative circles in Washington.
In an editorial, the Wall Street Journal said that by conditioning aid to Israel, Mr Biden risks encouraging Hamas into thinking it can avoid making a ceasefire deal with Israel.
Mr Biden is trying to pressure Israel into drawing up a comprehensive plan to protect civilians if it invades the southern city of Rafah, where more than a million displaced people are sheltering.
