GENEVA, Oct 10 (Reuters) - The head of the United Nations humanitarian relief agency on Tuesday (Oct 10) called for the immediate release of all people who have been taken hostage in the war between Israel and Palestinian Hamas militants.

"My message to all sides is unequivocal: The laws of war must be upheld," UN aid chief Martin Griffiths said in a statement.

"Those held captive must be treated humanely. Hostages must be released without delay."

Israeli Defence Minister Yoav Gallant said on Monday said the country would escalate measures against the Hamas-controlled Gaza Strip to a "total blockade" including a ban on admitting food and fuel.

"Throughout hostilities, civilians and civilian infrastructure must be protected. Civilians must be allowed to leave for safer areas," Griffiths said. "And humanitarian relief and vital services and supplies to Gaza must not be blocked."

Griffiths comments echoed that of UN Human Rights chief Volker Turk, who said earlier on Tuesday that Israel's "imposition of sieges that endanger the lives of civilians by depriving them of goods essential for their survival is prohibited under international humanitarian law".

Photo from Reuters