Hospital officials in the al-Quds hospital in Gaza City’s Tal al-Hawa districts alleged that a fire was sparked by “phosphorous shells”.

The fires that are a result of the use of phosphorous shells cannot be put out with water and so they are a challenge to put out for hospital workers.

One hospital official was quoted as saying, "we have been able to control the fire in the hospital, but not in the administrative building."

Over 500 Palestinians were hiding in the al-Quds hospital, hoping that they would be safe from Israeli tanks and warplanes. They were wrong.

Just east of Gaza City, Israeli tanks hit two other hospitals as the Israeli Army and Air Force coordinated a devastating attack on Gaza City and throughout surrounding suburbs.

The Israeli Air Force also bombed the UN headquarters in the city center of Gaza City, setting ablaze stockpiles of humanitarian aid, including food and medical aid that is desperately needed by the citizens of Gaza. It is also estimated that about 700 Palestinians were hiding from Israel’s onslaught in the UN building when it was set ablaze.

Israel’s actions on Thursday are starting to make it clear that Gazans have no safe places to hide from Israeli warplanes and tanks as they continue to push deeper and deeper into the tiny coastal region of Gaza that’s home to 1.5 million Palestinians.

Director of UNRWA operations in Gaza, John Ging also accused Israeli forces of using phosphorous shells in their offensive. Ging has stated that the fires that phosphorous shells create, "are phosphorus fires, so they are extremely difficult to put out because, if you put water on, it will just generate toxic fumes and do nothing to stop the burning."

Israel has so far been accused on multiple occasions, by multiple witnesses of using white phosphorous shells in Gaza, as reported by Al Jazeera between December 29th and January 9th. The use of white phosphorous shells in the manner that Israeli forces have been using them, in densely populated areas (Gaza being one of the most densely populated areas in the world) was banned in the 1980 convention titled 'Convention on Prohibitions or Restrictions on the Use of Certain Conventional Weapons Which May Be Deemed to Be Excessively Injurious or to Have Indiscriminate Effects' (entered into force in December 1983 and is an annex to the Geneva Conventions 1949).

Although, Israel insists all weapons used in the conflict comply with international law.

A Red Crescent office near Gaza City and the main mosque in the southern city of Rafah were also shelled as the Israelis pushed deeper into the Strip.

Al Jazeera reported that Ban Ki-moon, the UN secretary general, strongly condemned the incident and demanded a full explanation from Tzipi Livni, the Israeli foreign minister, during talks held on Thursday in Tel Aviv.