STORY: The U.N.'s top court has ordered Israel to immediately halt its military assault on Rafah in southern Gaza.

It is a landmark emergency ruling made as part of South Africa's case accusing Israel of genocide.

The International Court of Justice, also known as the World Court, has no means to enforce its order.

However, the decision is a stark sign of Israel's growing global isolation over its devastating campaign in Gaza.

That's particularly since it began its offensive against Rafah this month, against the pleas of its closest ally, the United States.

On Friday (May 24), World Court President Nawaf Salam said conditions had deteriorated in the Palestinian enclave since the court last ordered Israel to take steps to improve it.

"The court is not convinced that the evacuation efforts and related measures that Israel affirms to have undertaken to enhance the security of civilians in the Gaza strip, and in particular those recently displaced from the Rafah governorate, are sufficient to alleviate the immense risk to which the Palestinian population is exposed as a result of the military offensive in Rafah."

Israel launched its air and ground war on Gaza after Hamas-led militants stormed into southern Israel last year, killing around 1,200 people and seizing more than 250 hostages according to Israeli tallies.

Gaza's health ministry says more than 35,000 Palestinians have been killed in Israel's offensive.

Rafah, Israel says, is serving as a stronghold for thousands of Hamas fighters and senior commanders.

It began its armored attack on the city earlier this month - forcing hundreds of thousands of Palestinians to flee.

Rafah had become a refuge for around half Gaza's 2.3 million population.

It's also been the main route in for aid.

International organizations say Israel's operation has cut off Gaza and raised the risk of famine.

"...the humanitarian situation is now to be characterised as disastrous."

The World Court ordered Israel to open the Rafah crossing between Egypt and Gaza to allow in humanitarian aid.

Israel must also provide access for investigators, it added, and report back on its progress within one month.

South Africa's international relations department welcomed the ruling as "groundbreaking", saying it is the first time "explicit mention is made for Israel to halt its military action in any area of Gaza."

Israel has repeatedly dismissed the South African case's accusations of genocide as baseless.

It argues its operations are self-defense and targeted at Hamas militants.

On the eve of Friday's decision an Israeli government spokesperson said that "no power on Earth will stop Israel from protecting its citizens and going after Hamas in Gaza."