The UN Security Council has adopted a binding resolution compelling states to prevent their nationals joining jihadists in Iraq and Syria.
US President Barack Obama chaired the session and said nations must prevent the recruitment and financing of foreign fighters.
Meanwhile US and Arab jets bombed Islamic State (IS) targets in Syria for a third night, the US said.
Obama urged global efforts to dismantle the IS "network of death".
The US-drafted resolution was adopted unanimously.
It requires signatories to "prevent and suppress recruiting, organising, transporting, and equipping" of foreign fighters.
The latest air strikes targeted small-scale oil refineries controlled by IS, and which generate as much as $2m a day in revenue, the US military said late on Wednesday.
It said an initial assessment showed they had been successful.
The US launched air raids against IS militants in Iraq last month and on Monday expanded the strikes into Syria, with the participation of Gulf Arab allies.
Speaking at the UN, British Prime Minister David Cameron said the UK was ready to "play its part" in fighting Islamic State, which he called an "evil against which the whole world must unite".
A video released by Islamic State's official Al-Raqqa site on 23 September 2014 purportedly showing new recruits.
He told the UN council session that the Iraq and Syria conflicts were attracting young recruits from prosperous countries.
The UK Parliament will be recalled on Friday to discuss Britain's possible role in air strikes on IS targets.
Obama said "the words spoken here today must be matched and translated into action... within nations and between them, not just in the days ahead but for years to come".
In his earlier speech to the UN General Assembly he condemned IS, saying "there can be no reasoning - no negotiation - with this brand of evil".
More than 40 countries had offered to join the anti-IS coalition, he said.
IS aims to set up a hardline caliphate.
The well-armed Sunni Muslim militants have seized a huge swathe of Syria and Iraq, forcing whole communities to flee in terror.
They have beheaded Western hostages and have persecuted Christians, Yazidis and Shia Muslims, whom they treat as heretics.
An image grab taken from a video released by Islamic State group's official Al-Raqqa site via YouTube on 23 September 2014, allegedly shows Islamic State (IS) group recruits riding in armed trucks in an unknown location.
IS fighters have seized large areas in Iraq and Syria and declared a caliphate.
Meanwhile, more than 120 Islamic scholars signed an open letter to IS, condemning its ideology.
Muzammil Siddiqi, one of signatories and chairman of the Fiqh Council of North America, which interprets Islamic religious law, said: "It is forbidden in Islam to kill the innocent."
"It is forbidden in Islam to kill emissaries, ambassadors and diplomats. Hence, it is forbidden to kill the journalists and aid workers."
Map showing areas hit by US-led air strikes against Islamic State militants in Syria - 24 September 2014.
At the UN, Turkish President Recep Tayyip Erdogan accused the international community of not doing enough to help his country stem the flow of foreign fighters into Syria.
He told the Security Council said the fighters' home countries should co-operate better with Turkey to stop them getting through.
A resident walks upon the debris of buildings which were damaged in what activists say was one of Tuesday's US air strikes in Kfredrian, Idlib province, 24 September 2014.
Buildings in Raqqa were damaged by the US-led air strikes in Syria.
The IS advance has created a refugee crisis in Turkey.
Aid agencies said some 130,000 Kurdish refugees, most of them from Kobane, crossed into Turkey at the weekend.
The US has launched nearly 200 air strikes against IS in Iraq since August.
The US said Saudi Arabia, the United Arab Emirates, Jordan, Bahrain and Qatar had all "participated in or supported" the strikes on IS in Syria this week.
The strikes on Tuesday also targeted Khorasan, a shadowy group of al-Qaeda fighters in Syria's Aleppo province.
The US military says it is investigating whether the attack killed Khorasan's leader Mohsin al-Fadhli.
The Dutch government says it will deploy six F-16 fighter jets to join the US-led air campaign. The Netherlands will also send about 130 military trainers to Iraq.
