The US has described South Africa's filing at the International Court of Justice (ICJ) accusing Israel of committing genocidal acts in Gaza as "meritless".
"We find this submission meritless, counterproductive, and completely without any basis in fact whatsoever," US National Security Council spokesperson John Kirby told a Wednesday press briefing at the White House.
State Department spokesperson Matthew Miller separately said the US was "not seeing any acts that constitute genocide".
He added: "That is a determination by the State Department."
Pretoria's filing of its case at the United Nations' highest court has been welcomed by Palestinian rights groups Al-Haq, Al Mezan, and the Palestinian Centre for Human Rights, who said it was a "principled move".
The Organisation of Islamic Cooperation, which has 57 member states, also welcomed the submission.
The OIC called upon the ICJ to "respond expeditiously and take urgent measures to stop this mass genocide being perpetrated by the Israeli defence forces in the occupied Palestinian territories".
South Africa asked the ICJ on Friday for an urgent order declaring that Israel was in breach of its obligations under the 1948 Genocide Convention in its war on Gaza.
"The State of Israel will appear before the International Court of Justice at The Hague to dispel South Africa's absurd blood libel," Israeli government spokesman Eylon Levy told an online briefing on Tuesday.
"We assure South Africa's leaders, history will judge you, and it will judge you without mercy."
South Africa has for decades backed the Palestinian cause for statehood in territories illegally occupied by Israel. It has likened the plight of Palestinians to those of the Black majority in South Africa during the apartheid era, a comparison Israel strongly denies.
The ICJ, sometimes known as the World Court, is the United Nations' venue for resolving disputes between states. Israel's foreign ministry has said the suit was "baseless".
Lawyers representing South Africa are preparing for a hearing scheduled on 11 and 12 January, Clayson Monyela, a spokesperson for South Africa's Department of International Relations and Cooperation, said on social media platform X.
The ICJ has said the sessions on these two dates will relate to South Africa's request for the court to indicate provisional measures to "protect against further, severe and irreparable harm to the rights of the Palestinian people under the Genocide Convention" and ensure Israel complies with its obligations under the convention "not to engage in genocide, and to prevent and to punish genocide".
The current Gaza war began on 7 October after Hamas and other Palestinian militants carried out an attack inside Israeli territory, killing around 1,140 people in Israel, according to an AFP tally based on official Israeli figures.
Israel has since conducted an air and land assault on Gaza that has killed more than 22,400 people, according to the territory's health ministry.
Hospitals and residential buildings have been attacked, as has southern Gaza, the part of the territory to which Israel previously told civilians to evacuate.
Levy listed a series of measures Israel's military has taken to minimise harm to non-combatants, Reuters reported without elaborating.
He said Hamas bore full moral responsibility for the war it started and was "waging from inside and underneath hospitals, schools, mosques, homes and UN facilities".
Hamas denies using Gaza's population as human shields.
The Israeli military was unable to prove the Palestinian group had a base under Gaza's biggest hospital, al-Shifa, after raiding it in November.
Widespread concern has been expressed about the fate of Gaza's civilian population.
"As evacuation orders and military operations continue to expand and civilians are subjected to relentless attacks on a daily basis, the only logical conclusion is that Israel's military operation in Gaza aims to deport the majority of the civilian population en masse," Paula Gaviria Betancur, UN special rapporteur on the human rights of internally displaced persons, said last month.
Levy said, without elaborating, that South Africa was complicit in Hamas's crimes against Israelis.
(Reuters, AFP, The New Arab)