World Council of Churches general secretary Rev. Jerry Pillay has condemned the killing of aid workers in Gaza, and extended condolences to the families and friends of those who died in an Israeli airstrike.

The families of the aid workers are in shock and mourning upon hearing the news that an Israeli airstrike killed seven people working for World Central Kitchen.

Three of the workers killed were former British servicemen.

The strike prompted multiple charities to suspend food deliveries to Palestinians on the brink of starvation.

The deaths of the aid workers have threatened to set back efforts to open a maritime corridor for aid from Cyprus to help ease the desperate conditions in Gaza.

Famine is "projected and imminent" in the northern half of Gaza, a UN-backed report said last month, and according to Oxfam, since December, the number of people in the Palestinian territory facing "catastrophic levels" of hunger has nearly doubled.

Nearly 200 humanitarian workers have been killed in Gaza, including close to 180 UN staff in six months as over 33,000 Palestinians, mostly women and children, were killed, and over 1,200 are dead in Israel, the UN Human Rights office said on April 5.

Humanitarian workers must never be targets in conflict, said Pillay.

"It is tragic that people who give their time in serving others have to lose their own lives," said the WCC head.

"Such attacks which take the lives of innocent people are absolutely unacceptable and cannot be justified at any level.

"We invite all WCC member churches to join in raising their voices in prayer for justice, peace, and reconciliation in Gaza."

Pillay noted, "The UN Security Council approved on 25 March a long-awaited resolution on Gaza, demanding an immediate ceasefire and the immediate release of all hostages.

"This resolution must be implemented, and these senseless killings of innocent people must stop.".

Jeremy Laurence, a spokesman for the UN High Commissioner for Human Rights said in Geneva that more than 1,200 are dead in Israel and hundreds injured in the conflict that has unfurled since Hamas attacked Israel and took more than 200 hostages into Gaza.

He said that more than 100 hostages remain in captivity, while vast swathes of Gaza have been bombed into oblivion, with churches targeted as well, where Israel has said Hamas operatives use for cover.

"The Gaza Strip has changed forever," said the UN official.