"With a military siege in place, humanitarian organizations including the ICRC will not be able to assist such a massive displacement of people in Gaza," ICRC said in a statement.
The ADL, Jerusalem Center for Public Affairs, NGO Monitor, Middle East Forum, and StandWithUs are among the signatories of the open letter.
Parents bringing their children to swimming classes for the first time are surprised to see Tattar standing on two crutches.
"Attacks against healthcare including prevention of access to persons injured are extremely concerning," said WHO spokesperson Christian Lindmeier.