The Red Cross initially refused to take part in Hamas's ceremony during the return of the four slain hostages, Shiri, Ariel, and Kfir Bibas, as well as Oded Lifshitz, Channel 12 reported on Thursday.
The terror group subsequently threatened not to transfer the slain hostages, according to the report.
During the release of the hostages, a Red Cross representative signed Hamas documents on a stage in Khan Yunis in the southern Gaza Strip, after which Hamas terrorists handed over the coffins to Red Cross vehicles.
The Red Cross then transferred the coffins to the custody of IDF and Shin Bet (Israel Security Agency) forces within the Gaza Strip.
'Degrading treatment unacceptable'
On Wednesday, ahead of the expected release, the Red Cross called for privacy and dignity in the release.
"We must be clear: any degrading treatment during release operations is unacceptable," the International Committee of the Red Cross (ICRC) said in a statement.
The four coffins of the slain hostages arrived at the L. Greenberg Institute of Forensic Medicine at Abu Kabir for identification.
At the end of the identification process, an official announcement will be given to the families.
The coffins entered Israeli territory accompanied by IDF and Shin Bet (Israel Security Agency) forces.
Upon reception of the coffins, they were wrapped with Israeli flags, and the Military Rabbinate chief, Brigadier-General Rabbi Eyal Krim, recited Psalm 83. IDF officers transported the vehicles to the vehicles.
The IDF added that the episode was dutifully recorded with photos and videos but that nothing will be distributed to the public until and if the families of the deceased so approve.
Reuters contributed to this report.