The United Nations is running out of secure locations for its staff in Gaza due to the ongoing Israeli military attacks, just as a polio vaccination campaign is scheduled to begin next week, Under-Secretary-General for Safety and Security Gilles Michaud said on Tuesday.

As "Israel" broadens its onslaught and expands its invasion into formerly designated "safe zones", it continues to push Palestinians into smaller and smaller sections of the Strip. Just in August, nine evacuation orders were issued, encompassing locations the IOF had already classified as "humanitarian zones".

According to The Wall Street Journal, Gaza's 2.2 million residents are now mostly restricted to a region of around 15 square miles, less than Manhattan's footprint.

"Like most Palestinians in Gaza, we are running out of safe spaces for our own staff," Michaud said.

Read more: Over 60% of essential meds unavailable in Gaza due to Israeli blockade

'Long list of unbearable threats'

The Palestinian Health Ministry in Gaza reported earlier this month the first case of poliovirus in a 10-month-old infant who had not received any vaccination for polio in the city of Deir al-Balah.

He pointed out that the Israeli "mass evacuation orders are the latest in a long list of unbearable threats to UN and humanitarian personnel," adding that "the timing could hardly be worse".

"Humanitarians have been in the crosshairs" throughout the Israeli war on Gaza, which is "by far the deadliest on record for the United Nations," he continued.

The Israeli occupation army's "actions this weekend compound existing security threats and seriously impact the pace at which we can deliver [aid], safely. These constraints are beyond our control," Michaud asserted.

Read more: Israeli 'evacuation orders' deprive 1mln Palestinians of planned aid

The senior UN official said that "in line with international humanitarian law, our ability to provide assistance rests on the responsibility by parties to conflicts to do everything in their power to keep our colleagues safe."

"The women and men who risk their lives to deliver humanitarian aid need a safe and consistent place from which to work," he said, urging all parties "to respect international law and their commitments under the UN Charter to ensure the safety and security of UN personnel and premises."

However, despite all the threats, "The United Nations is determined to stay in Gaza to deliver life-saving aid for and with Palestinian civilians," he concluded.

The United Nations announced last week that a polio vaccination campaign targeting over 600,000 children in Gaza will commence soon, with a second round scheduled to take place one month later.

On day 326 of the Israeli genocide in Gaza, the total number of Palestinians killed since the ongoing Israeli war started on October 7 has risen to 40,476, and those injured to 93,647, the Health Ministry said on Tuesday in its daily report.

While a number of victims were transported to partially functioning hospitals and medical centers, others remain trapped beneath the rubble, with defense and rescue crews unable to reach them, the statement pointed out.

Read more: Israeli war on Gaza destroys sewage systems, sparks disease outbreaks