An Israeli airstrike triggered a fire that killed 45 people in a tent camp in the Gazan city of Rafah, officials said on Monday, prompting an outcry from global leaders who urged the implementation of a World Court order to halt Israel's assault.

Palestinian families rushed to hospitals to prepare their dead for burial after a strike late on Sunday night set tents and rickety metal shelters ablaze.

Israel's military, which is trying to eliminate Hamas in Gaza, said it was investigating reports that a strike it carried out against commanders of the Islamist militant group in Rafah had caused the fire.

Prime Minister Benjamin Netanyahu said the strike had not been intended to cause civilian casualties.

"In Rafah, we already evacuated about 1 million non-combatant residents and despite our utmost effort not to harm non-combatants, something unfortunately went tragically wrong," he said in a speech in parliament that was interrupted by shouting from opposition lawmakers.

Survivors said families were preparing to sleep when the strike hit the Tel Al-Sultan neighbourhood where thousands were sheltering after Israeli forces began a ground offensive in the east of Rafah over two weeks ago.

More than half of the dead were women, children, and elderly people, health officials in Hamas-run Gaza said, adding that the death toll was likely to rise from people with severe burns.

Israel's military said Sunday's strike, based on "precise intelligence", had eliminated Hamas' chief of staff for the second and larger Palestinian territory, the West Bank, plus another official behind deadly attacks on Israelis.

That followed the interception of eight rockets fired towards Israel from the Rafah area in Gaza's southern tip.

Israel has kept up its offensive despite a ruling by the top UN court on Friday ordering it to stop, saying the court's ruling grants it some scope for military action there. The court also reiterated calls for the immediate and unconditional release of hostages held in Gaza by Hamas.

French President Emmanuel Macron said he was "outraged" over Israel's latest attacks. "These operations must stop. There are no safe areas in Rafah for Palestinian civilians," he said on X.

German Foreign Minister Annalena Baerbock and the EU foreign policy chief Josep Borrell said the International Court of Justice ruling against action in Rafah must be respected. (Reuters)