UNITED NATIONS, May 30 (Xinhua) -- Israel has blocked the entry of UN aid into Gaza from Monday to Wednesday, while a new U.S.-run aid operation has been confounded by chaos, said a UN spokesman on Thursday.

Although Israel allowed hundreds of truckloads of aid into the Kerem Shalom/Karem Abu Salem crossing, the United Nations was not allowed to pick them up on the Gaza side on Monday, Tuesday and Wednesday, said Stephane Dujarric, chief spokesman for UN Secretary-General Antonio Guterres.

A limited amount of aid was reportedly distributed by the new U.S.-run and Israeli-supported Gaza Humanitarian Foundation despite chaotic conditions that led to casualties during earlier attempts.

Dujarric, at a regular briefing, pointed to a statement from the UN Humanitarian Country Team in the occupied Palestinian territory, warning that the new militarized aid distribution system does not meet the needs of people in Gaza and violates humanitarian principles.

The spokesman reiterated the UN's stance that fundamental humanitarian principles are non-negotiable.

There were also reports of fatalities and scores of injuries among Gazans rushing to seek aid packages and in the looting of a World Food Programme (WFP) flour warehouse.

The WFP said that hungry people broke into its Al-Ghafari warehouse in Deir Al-Balah in Central Gaza on Wednesday.

"They were clearly in search of food supplies that had been pre-positioned there for distribution," Dujarric said. "Initial reports indicate that two people died and several were injured in the tragic incident."

"The fact that it was looted was a sign of the desperation of people who don't know when the next aid trucks will come in," he said.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) said the supplies allowed into Gaza after an 11-week blockade are just a trickle of the aid required to meet the immense needs of 2.1 million people at a time when populations across the Gaza Strip are at risk of famine.

In the past 10 days since Kerem Shalom reopened, nearly 900 trucks were approved to enter, but only 600 of them have been offloaded on the Gaza side, but have yet to be distributed into Gaza itself, said the spokesman.

OCHA warned that airstrikes and other attacks continued across the Gaza Strip.

On Thursday, as attacks intensified, Israeli authorities ordered the medical team in Al Awda Hospital in North Gaza to evacuate the only functioning hospital in North Gaza. The facility is overwhelmed with injuries and severely lacking medical supplies.

The office said that despite intense insecurity, the WHO and partners reached the hospital twice in the past week to assess the situation and transfer 57 critical patients to Al Shifa Hospital.

OCHA said that in Khan Younis, the health authorities in Gaza reported that the Red Cross field hospital in Al Mawasi was hit, causing injuries and spreading fear among patients.

In the West Bank, OCHA said that demolitions and the threat of demolition of Palestinian homes during Israeli forces' operations in northern areas continue unabated.

The office said that demolition operations continued in Nur Shams refugee camp in Tulkarm city on Thursday, where Israeli forces have been active since May 5.

OCHA warned that the operations are sweeping in scale, marked by mass forced displacement and the extensive destruction of Palestinian property and humanitarian infrastructure. The destruction further fuels aid needs of affected communities. ■