United Nations, July 23 : A new evacuation order for parts of Gaza, including from parts of a "humanitarian zone," reportedly is forcing families into overcrowded, sparse shelter areas, UN humanitarians said.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) on Monday said it received initial reports that families are starting to flee toward Deir al Balah and western Khan Younis, following Israeli military evacuation orders.

Both areas are already heavily overcrowded, with limited services and shelter spaces available, Xinhua news agency reported.

OCHA said the latest evacuation order includes areas located in the eastern part of what had been designated by the Israeli military and described as a "humanitarian zone" in Khan Younis.

OCHA said relentless hostilities and frequent evacuation orders are further devastating Gaza's health system, making it increasingly difficult for people repeatedly displaced to access essential services. In the latest challenge for the health system, Nasser Medical Complex in Khan Younis has issued a new call for people to donate blood, with reports the facility received dozens of casualties on Monday.

The UN Relief Agency for Palestinians, known as UNRWA, reported that Israeli forces shot at a UN convoy heading to Gaza City on Sunday. UNRWA Commissioner-General Philippe Lazzarini said there were no casualties, but UNRWA's teams, travelling in clearly marked UN armoured cars and wearing UN vests, had to take cover.

He said one vehicle was severely damaged while waiting near the Israeli forces' checkpoint south of Wadi Gaza. That vehicle left the convoy. After the teams re-assembled, they were able to reach Gaza City. Lazzarini said the convoy's movement was coordinated with the Israeli authorities. He said those responsible for the incident must be held accountable.

"It is extremely worrying," said Stephane Dujarric, chief spokesman for UN Secretary-General Antonio Guterres. "We have seen an unprecedented number of colleagues have been killed in this operation. We have seen what happened to the World Central Kitchen (WCK). We need to get to the bottom of this, and this also comes within the context of some very harsh words by a number of Israeli officials regarding UNRWA."

Israeli officials have repeatedly accused UNRWA employees of taking part in the deadly October 7 Hamas attack on Israelis.

Seven WCK employees were killed in an April Israeli drone attack on their convoy, previously cleared by authorities.

"As always, wherever we operate, we operate under the protection of the authorities of where we work," Dujarric told correspondents at a regular briefing. The United Nations in Gaza is not armed. We do not have armed security with us. It is incumbent on all the parties in this conflict to ensure the protection of the UN and all humanitarian workers."

He said humanitarian operations in Gaza will continue.

"Our humanitarian partners report that people in Gaza continue to face severe water shortages," OCHA said. "Between July 8-21, the daily average water supply was about 90,000 cubic meters, about a quarter of the amount produced before October of last year."

Damage to infrastructure, the lack of electricity and shortages of fuel, spare parts and chlorine continue to hamper water production, purification and sewage pumping. This is despite some improvements, including the installation of a solar-powered desalination plant in Deir al Balah, with the support of the UN Children's Fund (UNICEF).

The fund reported that, on average, one Palestinian child was killed every two days in the West Bank, including East Jerusalem, since October.

UNICEF Executive Director Catherine Russell said the situation has deteriorated significantly, coinciding with the escalation of hostilities inside Gaza.

/IANS