The Israeli military may have committed war crimes and crimes against humanity during last summer's Gaza war, Amnesty International has claimed.

The watchdog made the claims about Israel's conduct after it carried out four days of intense bombardment in retaliation for an attack by Hamas militants in which an Israeli soldier was captured.

Amnesty International's report said Israeli forces carried out disproportionate and indiscriminate attacks, killing at least 135 civilians over the four days.

It says the military failed to independently probe the incident and called on the International Criminal Court (ICC) to investigate.

Hamas, the Islamic militant group which rules Gaza, welcomed the report and the group's spokesman, Fawzi Barhoum, said the ICC should take "punitive measures" against Israel.

Israel's foreign ministry spokesman denounced the report - one of several the London-based watchdog has released on the Gaza war - as "fundamentally flawed".

Emmanuel Nahshon said "there is almost no mention of the military actions of Hamas and other Palestinian terrorist organisations".

The 50 days of fighting in Gaza last year was the third and most devastating war between Hamas and Israel since the Islamic militants seized control of the territory in 2007 from the rival Palestinian Authority, dominated by President Mahmoud Abbas' Fatah Party.

More than 2,200 Palestinians, including hundreds of civilians, and 73 people on the Israeli side were killed in the fighting.