OPEC siege

On December 21, 1975, six militants attacked the semi-annual meeting of OPEC leaders in Vienna, Austria; the attackers took more than 60 hostages after killing an Austrian policeman, an Iraqi OPEC security officer, and a Libyan economist. Several other individuals were wounded. The self-named "Arm of the Arab Revolution" group was led by Carlos the Jackal. The siege resulted in complex diplomatic negotiations. It ended two days later, after flights to Algiers and Tripoli, with all the hostages and terrorists walking away from the situation. The fact that this was one of the first times that Arab states were targeted by terrorists also led to them being more cooperative in developing antiterrorism efforts at the United Nations.
On December 21, 1975, Saudi Arabian Minister of Petroleum Ahmed Zaki Yamani and the other oil ministers of the members of OPEC were taken hostage in Vienna, Austria, where the ministers were attending a meeting at the OPEC headquarters at Dr-Karl-Lueger-Ring 10 . The hostage attack was orchestrated by a six-person team led by Venezuelan terrorist Carlos the Jackal . The self-named "Arm of the Arab Revolution" group called for the liberation of Palestine. Carlos planned to take over the conference by force and kidnap all eleven oil ministers in attendance and hold them for ransom, with the exception of Ahmed Zaki Yamani and Iran's Jamshid Amuzegar, who were to be executed.

Wikipedia