The United Nations Security Council has demanded all states act to prevent their nationals joining jihadists in Iraq and Syria, making it a serious criminal offence to travel abroad to fight with militant groups.
At a meeting chaired by US President Barack Obama. the council unanimously adopted a binding resolution compelling countries to prevent and suppress recruitment and travel of militant fighters to foreign conflicts.
The UN action was prompted by the rise of Islamic State (IS) which Mr Obama described as a "network of death". He urged more countries to back a US-led campaign against the militants in Iraq and Syria.
The United States launched air raids against IS militants in Iraq last month and on Monday night expanded the strikes into Syria, with the participation of Gulf Arab allies.
In a new round of bombings, US, Saudi and Emirati warplanes broadened their bombardment to target the oil fields in eastern Syria that have helped fund the jihadist group's rise from rebel faction to alleged global threat, AFP says.
IS now controls several oilfields in Syria and Iraq, and sales of smuggled crude oil have helped finance its offensive in both countries.
'Language of force'
Mr Obama urged those who have joined the extremist group to "leave the battlefield while they can".
He said more than 40 nations have offered to join the coalition against the militants in Iraq and Syria.
"The only language understood by killers like this is the language of force. So the United States of America will work with a broad coalition to dismantle this network of death," Mr Obama said.
Earlier, the US military said warplanes had hit IS vehicles and arms dumps near Abu Kamal on the Syria-Iraq border and Deir al-Zour in the east of Syria over a 24-hour period.
In Iraq there were strikes west of Baghdad and southeast of Irbil, near Kurdish territory. Earlier there were air strikes on IS near the border with Turkey.
In Britain, parliament was being recalled tomorrow to discuss whether British forces should take part in the American-led air strikes.
Meanwhile the Dutch Government says it will send six F16 strike aircraft to the region and more than 350 military personnel.