Arab states agreed Sunday to take the "necessary measures" and were prepared to cooperate internationally to confront Islamic State militants, Arab League chief Nabil al-Arabi said.
At the start of a foreign ministers' meeting in Cairo, Arabi had called for a political and military confrontation with the jihadists and other militants he said threatened the existence of Arab states.
He later stopped short of explicitly backing US air strikes targeting IS jihadists who control swathes of Iraq and Syria.
"The Arab foreign ministers have agreed to take the necessary measures to confront terrorist groups including" IS, Arabi said at a news conference.
"International cooperation is included; international cooperation on all fronts," he said.
The ministers agreed to "take all measures to counter terrorism: political, security and ideological," he added, without spelling out what these measures would be.
His remarks came as the United States expanded air strikes against the militants and sought wider regional backing for its campaign.
Arabi had earlier urged the foreign ministers to take "a clear decision for a comprehensive confrontation, militarily and politically".
Iraq had welcomed US President Barack Obama's plan for an international coalition against jihadists as a "strong message of support", after repeatedly calling for aid against the militants.
Obama outlined the plan at a NATO summit Friday for a broad coalition to defeat IS, which led an offensive that overran parts of Iraq in June and also holds significant territory in neighbouring Syria.
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- Obama's IS 'game plan' -
He said Sunday he will make a speech on Wednesday to lay out his "game plan" to deal with and ultimately defeat IS, but warned he would not wage another ground war in Iraq.
IS, originally an Al-Qaeda affiliate in Iraq that expanded in the Syrian conflict, claims its chief Abu Bakr al-Baghdadi is the rightful leader, or Caliph, of all Muslims.
The group's astonishing rise in Syria and Iraq caught the weak government in Baghdad, and much of the region, off guard.
Arabi said IS posed a threat to the entire region.
"What is happening in Iraq is that the terrorist organisation not only threatens a state's authority, but threatens its very existence and the existence of other states," he said.
Arab countries have participated in Western-led military campaigns in the past, including the first Gulf War and the aerial campaign against the late Libyan dictator Moamer Kadhafi.
The United States on Sunday expanded its month-long air campaign against the militants in Iraq's Sunni Arab heartland, hitting IS fighters west of Baghdad as Iraq troops launched a ground assault.
Aside from fighting in Iraq, Arab states are concerned that IS is coordinating with domestic extremists and that militants who travelled to join the group may conduct attacks on their return home.
In Egypt, several militants who have carried out attacks on security forces since the army overthrew Islamist president Mohamed Morsi in 2013 had travelled to fight in Syria.
Egypt's main militant group, Ansar Beit al-Maqdis, has not publicly pledged its loyalty to IS, but has referred to the jihadists as "brothers".