In a joint statement, the heads of multiple United Nations agencies said they were "alarmed by the sustained violations of the rules of war and international humanitarian law" in the region.

"Even wars have rules, and these rules must be respected," the statement from the UN Inter-Agency Standing Committee said.

The joint statement -- penned by UN humanitarian chief Tom Fletcher along with the heads of the UN agencies for human rights, health, food, refugees and children among others -- decried the soaring toll since the Middle East war erupted on February 28.

"In just the last month across the Middle East, thousands of civilians have been killed and injured. Hundreds of thousands have been displaced, many multiple times," it said.

"The numbers continue to rise and essential services are increasingly difficult to access.

"Health workers, hospitals and ambulances have been targeted. Schools have been struck. Civilian infrastructure - including bridges, residential buildings, houses, water facilities and power plants - has been destroyed," it said.

The agency chiefs voiced particular concern about the impact on "women and children and others with specific needs", as well as on global supply chains, "with food and fuel prices on the rise".

At the same time, they highlighted that "our humanitarian colleagues have been caught up in the hostilities".

Just since the beginning of this year, they said, "14 aid workers have been killed or injured in the Occupied Palestinian Territory, eight in Iran and five in Lebanon".

"This is an alarming toll."

The agency chiefs said they "strongly condemn all attacks on civilians, including humanitarian and health workers, as well as civilian objects".

"We demand that all parties - whether Member States of the United Nations or armed groups - respect their legal obligation to protect civilians, including humanitarian personnel, and civilian infrastructure," they said.

"All violations must be met with accountability."