A new military alliance made up of 34 Muslim nations has been formed to fight terror.
Saudi Arabia is leading the joint operation based in the kingdom's capital Riyadh.
An announcement by the Saudi Press Agency said the coalition was established because terrorism "should be fought by all means and collaboration should be made to eliminate it".
While Saudi Arabia's regional rival, Shiite Iran, is not part of the coalition, the alliance brings together diverse Muslim countries from several continents.
It includes Mali, Malaysia, Pakistan, Lebanon and Egypt as well as neighbouring Gulf countries such as the United Arab Emirates.
Saudi Arabia is currently leading a military intervention in Yemen against Shiite rebels and is part of the US-led coalition bombing the so-called Islamic State (IS) in Iraq and Syria.