The chiefs of staff of member states in an Islamic military coalition against terrorism made the pledge during their first meeting in Riyadh.
The meeting discussed "ideological, media, financial and military" aspects to combat terrorism, spokesman for the alliance Brig. Gen. Ahmed Assiri said.
The spokesman said the attendance of 39 Muslim nations, not all of which were members of the alliance, "sends a strong message on importance and nature of the alliance," adding that the force is needed in the face of the Islamic State group.
The meeting aims to draw up a unified strategy against terrorism, he said, adding that Saudi Arabia presented a paper to follow the resources of terrorism funding.
He emphasizes that the coalition will work in line with the international law and standards.
The coalition was announced in December last year by Saudi Defence minister Prince Mohammed bin Salman in a bid to establish a unified Muslim body to fight terrorism.
It started through the establishment of a joint operations centre in Riyadh.