The United States issued on Friday a stunning criticism of Israel’s use of American weapons in the Gaza conflict, after Israeli forces intensified operations around the southern city of Rafah, where more than a million displaced people are sheltering, AFP reports.

Israel’s main international ally said it was “reasonable to assess” that Israel has used weapons in ways inconsistent with international humanitarian law during the seven-month conflict, but said it could not reach “conclusive findings” and stopped short of blocking shipments.

Relations between the two allies sunk earlier in the week after US President Joe Biden threatened to halt some arms deliveries if Israel went ahead with a full-scale assault on Rafah threatened by Prime Minister Benjamin Netanyahu.

The US has warned that the reputational damage Israel will suffer if it storms a city where an estimated 1.4 million civilians are sheltering will far outweigh any possible military gain.

UN chief Antonio Guterres said Friday that Gaza risked an “epic humanitarian disaster” if Israel launched a full-scale ground operation in Rafah, while France urged Israel to cease its operations in Rafah “without delay”.

The Israeli premier has said repeatedly that Israel cannot defeat Hamas and eliminate any possibility of the militant group repeating its bloody October 7 attack without sending ground troops into Rafah in search of remaining Hamas fighters.

Netanyahu struck a defiant tone on Thursday, vowing: “If we have to stand alone, we will stand alone.” The White House renewed its opposition Friday but said it saw no major operation yet against the city.

“We’re obviously watching it with concern, of course, but I wouldn’t go so far as to say what we’ve seen here in the last 24 hours connotes or indicates a broad, large (or) major ground operation,” National Security Council spokesman John Kirby told reporters.