Khan Younis, January 25 (RHC)-- Several people have been killed after a United Nations shelter in Gaza‘s southern city of Khan Younis was shelled by Israeli forces, the Gaza head of the UN agency for Palestinian refugees has said.

“Two tank rounds hit building that shelters 800 people – reports now 9 dead and 75 injured,” Thomas White, the Gaza director of the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA), said on the social media platform X.

In a separate post earlier on Wednesday, White said the training centre sheltering displaced families had been set ablaze.  The number of victims is expected to rise, as the UN official said the incident had likely caused “mass casualties.”

UNRWA spokesman Adnan Abu Hasna, based in Rafah, told Al Jazeera the UN has been trying to send ambulances to the site in coordination with the Israeli army.  He said no warning had been issued by the Israeli military prior to the attack.

The agency has not been able to access the compound for the past 48 hours due to the presence of Israeli tanks in the area, Abu Hasna said, describing the situation as “very dangerous”.

“We tried to coordinate the exit of the IDPs [internally displaced persons] there but did not succeed unfortunately,” he added.  

Philippe Lazzarini, the head of UNRWA, condemned the attack on the shelter as “a blatant disregard of basic rules of war.”   “The compound is a clearly marked UN facility & its coordinates were shared with Israeli authorities as we do for all our facilities,” he wrote in a post on X, saying the number of those killed is likely higher.

Israel has continued intense attacks on Khan Younis, targeting medical facilities, among others.  Some 660 attacks on health institutions have been recorded in Gaza.   Gaza’s Ministry of Health on Wednesday said the Israeli army isolated the Nasser Medical Complex in Khan Younis after it was encircled and ground troops engaged in close-quarter combat with Hamas fighters.

The Palestinian Red Crescent Society (PRCS) also wrote on X that the Israeli army surrounded its headquarters and the El Amal Hospital in the southern city, enforcing restrictions on movement to and from the medical facility.

Khan Younis was once designated a “safe zone” for hundreds of thousands of Palestinians who evacuated from the northern parts and Gaza City at the start of the war.  Israeli soldiers on Monday advanced for the first time into al-Mawasi district near the Mediterranean coast west of Khan Younis.

Asmaa Abu Khudair, a Palestinian woman displaced from al-Mawasi to Rafah, said she fled the intense bombardment in the area after the building next to hers was attacked by the Israeli military.  “Their aircraft started firing.  All of a sudden, balls of fire started to fall on us,” she told Al Jazeera.  “The whole area was in flames, fire everywhere.  We started running, I pulled out one of my daughters, but my other daughter I couldn’t find.”

Abu Khudair said the flames grew bigger and she had to flee without her missing daughter.  “Do you understand when I say fire?”, she said in tears.  “I lost my daughter.  My husband was in his brother’s tent.”

“The following day, their bodies were recovered, totally charred,” she added.

At least 25,700 people have been killed and 63,740 wounded in Israeli attacks on Gaza since the war began on October 7.