The US-led coalition has bombed oil facilities used by Islamic State (IS) jihadists in Syria, as the world moves to choke off funding for what President Barack Obama branded a “network of death”.

American, Saudi and Emirati warplanes hit oil installations in eastern Syria controlled by IS, broadening the campaign they launched this week beyond military targets to economic assets.

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IS, which has imposed its brutal rule over swathes of Syria and Iraq, has been using such small-scale mobile refineries to generate up to $US2 million ($A2.16 million) in revenues per day, Washington said.

The strikes against the refineries killed 14 jihadists but also left five civilians dead, including a child, said the Syrian Observatory for Human Rights, a Britain-based monitoring group.

The raids came as Obama urged leaders gathered at the UN General Assembly to join the coalition and convinced the Security Council to back a resolution aimed at stemming the flow of foreign fighters joining IS.

Belgium and The Netherlands committed warplanes to Iraq and Britain said its parliament would vote Friday on following suit.

“The United States of America will work with a broad coalition to dismantle this network of death,” Obama told the UN.

“Today I ask the world to join in this effort.”

A Muslim “caliphate”

The Islamic State group seized large parts of Iraq in June, declaring a Muslim “caliphate” straddling Iraq and Syria and imposing its harsh interpretation of Islamic law.

It has committed widespread atrocities including mass executions of captured Iraqi soldiers, forced conversions of non-Muslims and the on-camera beheadings of Western hostages including two US journalists and a British aid worker.

Late on Wednesday, an IS-linked group in Algeria which had demanded France halt its participation in strikes in Iraq posted video footage of the execution of an abducted Frenchman.

President Francois Hollande condemned the “cruel and cowardly” murder of Herve Gourdel, a 55-year-old hiker who was kidnapped in an Algerian national park, and was to convene an emergency meeting of his defence council on Thursday.

The latest round of air raids focused on a dozen targets in eastern Syria.

“These 12 targets were what we call modular oil refineries,” Pentagon spokesman Rear Admiral John Kirby told CNN.

Alongside US aviation and cruise missiles, Saudi Arabia, Bahrain, the United Arab Emirates and Jordan have hit targets in Syria. Qatar is providing logistical support.

Syrian strikes

Previous strikes in Syria have hit IS positions, command centres, training compounds and vehicles, in their regional stronghold of Raqa and near the Syria-Iraq border.

The coalition has carried out some 20 strikes in Syria since the start of the week and Washington nearly 200 in Iraq since launching air raids there in early August.

More than 50 nations have joined the US-led coalition against IS, including key Arab states, and in recent days more countries have promised concrete military support.

Joining France, Belgium and The Netherlands said they would each send six F-16 fighter bombers to take part in the air campaign in Iraq.

The Netherlands will also deploy 250 military personnel and 130 trainers for the Iraqi military, and Greece said on Thursday it would send arms to Kurdish forces battling the jihadists.

Britain has yet to join the strikes but on the sidelines of the UN General Assembly Prime Minister David Cameron said the British parliament would hold an extraordinary session on Friday to vote joining the military campaign.