GAZA STRIP — United Nations humanitarians have suspended nighttime aid movements in Gaza for at least 48 hours following Israel's killing of staff from World Central Kitchen, or WCK, as more questions arise over Israel's explanation of the attack on their convoy.

"We have suspended our nighttime movements within the Gaza Strip for at least 48 hours to allow for further evaluation of the security issues that impacted our personnel on the ground," said Stephane Dujarric, spokesman for UN Secretary-General Antonio Guterres, on Wednesday.

The 48-hour suspension started on Tuesday following Monday's killing of WCK aid staff, he said.

He said the World Health Organization is still waiting for permission from the Israeli authorities to get access to Al Shifa hospital in northern Gaza. The WHO team is also planning to visit two other hospitals in northern Gaza, Sahaba and Ahli hospitals. However, no permission has been given to go to those sites.

In another setback to aid efforts in Gaza, a sea convoy of undelivered food returned to Cyprus on Wednesday after WCK aid workers' deaths.

A cargo ship carrying 240 metric tons of food that had been destined for the people of the besieged Palestinian enclave sailed back to Larnaca in Cyprus following the deadly attack, dropping anchor just outside the port.

A second ship, the Open Arms owned by a Spanish nonprofit working with WCK, arrived earlier.

The bodies of six foreign aid workers killed began the journey back to their home countries on Wednesday, as more questions swirled over Israel's explanation that a "misidentification" led to the attack on the convoy.

Criticism renewed

The deadly strikes on the convoy renewed criticism of Israel's conduct in the nearly 6-month-old conflict with Hamas and highlighted the risks that the military's bombardment poses to aid workers.

Israel's military chief Herzi Halevi announced the results of a preliminary investigation.

"It was a mistake that followed a misidentification — at night during a war in very complex conditions. It shouldn't have happened," he said, giving no further details.

Meanwhile, Ismail Haniyeh, head of Hamas' Political Bureau, affirmed on Wednesday the movement's commitment to its demands for a cease-fire in Gaza.

Haniyeh said in a speech that the demands include the withdrawal of the Israeli army from the Gaza Strip, the return of the displaced to their homes, entry of aid, lifting of the blockade, reconstruction, and a dignified prisoner exchange deal.

Meanwhile, the Palestinian delegation to the UN is pushing for a vote to be recognized as a full member state next month, Ambassador Riyad Mansour said on Wednesday.

"We are seeking admission. That is our natural and legal right," Mansour said, adding that he was pushing for an April 18 vote at the Security Council.

However, the United States earlier on Wednesday voiced its opposition to full Palestinian membership. US President Joe Biden has faced protests over the conflict in Gaza all over the country.

In a different move, Spain is set to recognize Palestine as a state. Spain's Prime Minister Pedro Sanchez unveiled his intention to recognize Palestine during an official visit to Jordan, Qatar and Saudi Arabia.

Sanchez, who has been strongly critical of Israel's offensive in Gaza, said Spain could recognize Palestine as soon as July. But he added that his country would also be "attentive to the decisions that will be taken (by the UN) in Brussels and New York".

Earle Gale in London contributed to this story.

Agencies-Xinhua