UNITED NATIONS, Feb. 6 (Xinhua) -- UN humanitarians on Friday expressed concern over reports of ill-treatment of Palestinian returnees via the Rafah border crossing with Egypt, amid deadly Israeli attacks on civilians.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) said that Israeli airstrikes, gunfire and shelling continue to be reported across civilian areas of the Gaza Strip, resulting in casualties and damage.

OCHA said Israeli forces on Thursday demolished the Jabalya Preparatory Boys' School of the UN agency for Palestine refugees, the last in a compound of six schools, leaving the entire compound destroyed.

The office said that civilians and civilian infrastructure must always be protected, and that they must never be targeted or used to shield military activities.

The UN Development Programme reported transporting 21 returnees on Thursday from the Israeli checkpoint to Nasser Hospital in Khan Younis, where OCHA and its partners operate a reception area, bringing the number of returnees received since Monday to 98.

The UN Human Rights Office (OHCHR) warned Thursday of a pattern of ill-treatment, abuse and humiliation of returnees by Israeli forces and by armed Palestinians allegedly backed by the Israeli military.

"Accounts indicate that some of the armed Palestinians handcuffed and blindfolded returnees, threatened and intimidated them, conducted searched and stole personal belongings and money," said the OHCHR. "Upon arrival at the Israeli checkpoint, returnees described violence, degrading interrogations, and invasive body searches."

The OHCHR said that the accounts point to a pattern of conduct that violates Palestinians' rights to personal security, dignity, and freedom from torture and other ill-treatment.

OCHA said that humanitarian movements inside Gaza continue to require coordination with Israeli authorities.

It said the United Nations attempted to coordinate 11 humanitarian missions on Thursday and Friday, of which six were fully facilitated. Four other missions faced long delays at holding points along the designated routes, resulting in only two of them fully accomplished.

The missions included the collection of water and sanitation supplies, fuel and other items, medical evacuation via the Rafah crossing and the transportation of returnees to Nasser Hospital. ■