Islamic State fighters at the Baiji oil refinery. Screenshot Via YouTube The United States has upped its intensity in the fight against ISIS, deploying airstrikes on trucks used by the militant group to smuggle oil through Syria, according to a report in The New York Times.

The Times reports that Col. Steven H. Warren, a spokesman for the US-led coalition, confirmed that airstrikes had destroyed 116 trucks carrying oil in the Deir al-Zour area of Syria. This marks the first time oil trucks have been targeted by the US in its campaign against ISIS, The Times reports.

The area is close to the country's eastern border with Iraq, and it is under the control of ISIS, also known as the Islamic State or ISIL.

The attacks were not a direct response to the Paris attacks on Friday, which ISIS has taken credit for. The operations had been planned for a while, The Times said, citing unnamed officials, as a means of disrupting what is one of the key revenue streams that allows ISIS to continue its operations.

The attacks did come almost immediately after a series of strikes carried out by French aircraft, which targeted "a command center, recruitment center for jihadists, a munitions depot, and a training camp for fighters" according to a statement from the French government.

Multiple coordinated attacks in Paris on Friday night that ISIS has taken credit for killed at least 129 people.

ISIS can make up to $40 million (£26.3 million) a month through producing and smuggling oil, according to The Times, while one unnamed Western oil worker told Reuters in September that "Islamic State makes not less than $2 million (£1.3 million) daily that allows them to pay salaries and maintain their operations." ISIS now controls most of eastern Syria's oil-producing areas.

Deir al-Zour, near where the attacks took place. The Iraqi border can be seen to the east Google Maps

Last week, US forces began to increase the volume of strikes on oil fields in Syria to disrupt ISIS' oil-producing operations, but the US had resisted attacking convoys out of fear of causing civilian casualties, according to The Times. This has allowed ISIS' distribution network to function virtually unchecked until now.

Fear of injuring civilians meant that numerous precautions were put in place by the US forces, according to The Times, including dropping leaflets around an hour before any strikes were carried out, warning civilians and drivers to get out of the immediate area.

Colonel Warren confirmed to the Times that around 295 trucks were in the area targeted by the airstrikes, which were carried out by four A-10 attack planes and two AC-130 gunships.

The campaign of bombing has been dubbed Tidal Wave II after the World War II attacks on Romanian oil production designed to slow Nazi Germany.