The UN agency for Palestinian refugees (UNRWA) called Tuesday to respect humanitarian pauses in the war-torn Gaza Strip to allow the vaccination of Palestinian children against polio.

The second phase of a polio vaccination campaign began on Monday for children under 10 in the central Gaza Strip.

"We cannot vaccinate children under a sky full of bombs," UNRWA said in a statement.

It said nearly 93,000 children were vaccinated and more than 76,300 children received Vitamin A on the first day of this three-day phase.

“All parties to the conflict must respect the agreed-upon humanitarian pauses to allow the roll-out of this campaign,” it added.

The first phase of the campaign concluded on Sept. 12 and included over 560,000 Palestinian children.

According to the UN, children in Gaza require two doses of the vaccine, each consisting of two drops administered orally.

On Wednesday, UNRWA said that around 400,000 people are trapped in northern Gaza amid an Israeli offensive in the area, jeopardizing the implementation of the second phase of the polio vaccination campaign.

Israel has continued its brutal offensive on Gaza since last year’s Hamas attack, despite a UN Security Council resolution demanding an immediate cease-fire.

More than 42,300 people have since been killed, mostly women and children, and over 99,000 others injured, according to local health authorities.

The Israeli onslaught has displaced almost the entire population of the territory amid an ongoing blockade that has led to severe shortages of food, clean water, and medicine.

Israel also faces a genocide case at the International Court of Justice for its actions in Gaza.