From Beirut , Carlos participated in the planning for the attack on the headquarters of OPEC ( Organization of the Petroleum Exporting Countries ) in Vienna . On 21 December 1975 , he led the six-person team ( which included Gabriele Kröcher-Tiedemann ) that attacked the meeting of OPEC leaders ; they took more than 60 hostages and killed three : an Austrian policeman , an Iraqi OPEC employee and a member of the Libyan delegation . Carlos demanded that the Austrian authorities read a communiqué about the Palestinian cause on Austrian radio and television networks every two hours . To avoid the threatened execution of a hostage every 15 minutes , the Austrian government agreed and the communiqué was broadcast as demanded
attack on the headquarters of OPEC
OPEC siege
Carlos the Jackal