The Israeli Defence Force (IDF) has been posting onto the Web videos and photographs it confiscated from members of the international flotilla, after hi-jacking the convoy and apprehending those it left alive.
The Foreign Press Association in Israel said it "strongly condemned" the use the material shot by foreign journalists, now being put out by the IDF spokesman's office as "captured material".
The material and/or equipment that was confiscated from journalists covering the events on the ships should be returned to its owners and their media organisations, the FPA said in a statement.
"The use of this material without permission from the relevant media organisations is a clear violation of journalistic ethics and unacceptable. In view of this we urge members to treat the material with appropriate caution."
The FPA called upon Israeli authorities to immediately clarify the source of the material.
The IDF's propaganda page is here. It has also been posting videos onto YouTube.
At least nine protesters were shot dead after the IDF attempted to board the biggest boat in the flotilla headed for blockaded Gaza. The full death toll may yet be higher.