Jerusalem, Jan. 15 : The United Nations on Thursday expressed its outrage against Israel after it targeted its headquarters in the Gaza Strip, injuring three of its employees.

Chris Gunness of the UN Relief and Works Agency (UNRWA) told Sky News that hundreds of people were taking refuge inside the compound when it was hit by "three white phosphorus" shells.

The weapons burn at extremely high temperatures, starting fires that cannot be put out with fire extinguishers.

Gunness confirmed that a blaze is raging in one of the buildings housing hundreds of tons of food aid due to be pushed out today.

UN Secretary General Ban Ki-Moon expressed his anger over the Israeli strike and demanded a full explanation from the Israeli authorities.

The number of dead in Gaza has reached an "unbearable point", he said, insisting elements are in place for the 20-day-old war to end "now".

According to Sky News, Israel insists it is only targeting Hamas militants but the headquarters of several media organisations have also reportedly been hit, injuring two cameramen.

Thursday''s strike comes despite reports of a cease-fire arrangement being worked out between the Hamas and Israel with the help of Egyptian mediators.

Egyptian mediators will put forward the Hamas point of view to senior Israeli defence official Amos Gilad when he visits Cairo for talks later today. The Hamas has said that it is ready for a conditional cease-fire arrangement. (ANI)