Human Rights Watch (HRW) has called for parties arming Israel and Palestinian groups to halt the transfer of weapons, warning that continued armament could escalate abuses in besieged Gaza.
The rights group said that weapons could be used to carry out unlawful attacks, making those providing arms complicit in war crimes.
HRW said that the US, UK, Germany and Canada must suspend arms sales and military assistance given to Israel as its forces have relentlessly and indiscriminately shelled Gaza, killing at least 10,328 people as of Tuesday. Almost half of the victims are children.
The rights group issued a similar warning to Iran, which allegedly backs Hamas.
"The United States, Iran and other governments risk being complicit in grave abuses if they continue to provide military assistance to known violators," HRW chief advocacy officer Bruno Stagno said.
The US, Israel’s biggest ally, has delivered vast quantities of weapons and ammunition to the country since the October 7 surprise Hamas attack by Israel. President Biden also requested $14.3 billion for further arms to the country in addition to the $3.8 billion in military aid received annually by Israel.
The UK has also licensed the sale of £442 million ($539 million) worth of arms to Israel since 2015, including aircraft, bombs, and ammunition. Canada and Germany have made similar deals.
Many rights groups, such as Amnesty International, have accused Israel of carrying out war crimes in the Gaza Strip since its bombardment of the besieged territory began.
At least 89 UN workers have been killed during the war, as well as over 40 journalists, both in Gaza and across the border in Lebanon.
Israel has used thousands of tons of explosives in populated areas, partially or fully destroying residential areas and key infrastructure.
Credible evidence also suggests that Israel has used white phosphorus in its military operations in Gaza and Lebanon, which can burn human flesh and lead to lifelong injuries.
HRW also urged Iran to cease supplying Hamas and other Palestinian groups with weapons. Over 1,400 Israelis were killed in the surprise cross-border attack on 7 October.
Hamas has also gone on to launch rockets into Israel since last month, and has kept more than 200 Israeli and other nationals hostage since.
Iran has denied claims that it was involved in Hamas’ attack last month.
In 2022, Hamas said Tehran provided them with $70 million in military assistance over an unspecified period.
HRW expressed its concerns as there appears to be no end in sight for Israel's onslaught on Gaza and likely retaliations from Hamas.
Israel has vowed to continue its attacks on Gaza until Hamas is "eliminated", despite the extraordinarily high civilian death toll from its bombing.