Palestinians gather at the site of Israeli strikes on houses in Jabalia refugee camp in Gaza Strip on Wednesday. Reuters

Israel hit Gaza's largest refugee camp with renewed air strikes on Wednesday, prompting UN rights officials to warn that targeting densely populated residential areas "could amount to war crimes."

Bombs struck the Jabalia camp for a second time in two days, pulverising buildings and, according to the Hamas-run health ministry, killing dozens of people.

The media witnessed extensive damage at the scene, with people frantically clawing through rubble to extract bloodied casualties.

Many nations backed Israel's right to strike back at Hamas, but as the civilian toll has mounted, so too has criticism of Israeli tactics.

According to Gaza's health ministry, 8,796 Gazans have been killed so far, mostly women and children. Whole neighbourhoods in Gaza have been levelled.

Palestinians check the bodies of victims lying down outside a hospital morgue in the Jabalia camp. AFP

Israeli forces had already struck the Jabalia camp on Tuesday, killing at least 47 people, according to an AFP count.

'War crimes'

The United Nations decried Israel's most recent bombings, joining a chorus of international condemnation from as far afield as Bolivia, which severed diplomatic ties in protest.

The UN's top human rights body — citing "the high number of civilian casualties" and scale of destruction — said it had "serious concerns that these are disproportionate attacks that could amount to war crimes."

Jordan recalled its ambassador to Israel "to condemn the Israeli war that is killing innocent people in Gaza".

People carry the body of a Palestinian near the site of Israeli strikes on houses, in Jabalia refugee camp. Reuters

Israel has rejected such accusations, saying Hamas deliberately uses civilian areas to hide command posts and arsenals that are used to attack Israeli civilians.

Hamas said seven of the 240 hostages it is holding, including three foreign passport holders, died in Tuesday's bombing, a claim that was impossible to verify.

The group's leader Ismail Haniyeh accused Israel of committing "barbaric massacres against unarmed civilians", saying it was covering its own "defeats".

Agence France-Presse