Human Rights Watch on Monday accused Israel of killing civilians as they attempted to flee a stricken neighbourhood of Gaza, in what it said would amount to a war crime.

In a report that cited Palestinians who managed to get out of Khuza'a, HRW said the attacks on the town near the southern city of Khan Yunis occurred at the end of July.

"Israeli forces in the southern Gaza town of Khuza'a fired on and killed civilians in apparent violation of the laws of war in several incidents between July 23 and 25," said the New York-based watchdog.

"Deliberate attacks on civilians who are not participating in the fighting are war crimes."

Civilians faced "grave dangers" in Khuza'a, including repeated shelling, lack of access to medical care, and coming under attack from the Israelis as they attempt to flee to Khan Yunis.

The report pointed out that while Israeli forces had warned people to leave Khuza'a prior to July 21, "the failure of civilians to abide by warnings does not make them lawful targets of attack."

"Warning families to flee fighting doesn't make them fair targets just because they're unable to do so, and deliberately attacking them is a war crime," said HRW's Sarah Leah Whitson.

Following more than three weeks of Israeli attacks on Gaza, the Palestinian death toll is believed to have reached 1820 as more than the quarter of the 1.8 million residents have been displaced.

*This story was edited by Ahram Online.