Warplanes from the United States-led coalition attacked and destroyed on Sunday an oil refinery held by the Islamic State of Iraq and Syria.

According to the Daily Star, the Syrian Observatory for Human Rights said that airstrikes carried out by the coalition on Sunday hit and destroyed two oil refineries in the de facto capital of the Islamic State, Raqqa, in Syria near the border with Turkey.

The weekend's airstrikes are the latest in the coalition's ongoing air campaign against positions held by the jihadists. The coalition has waged a sustained campaign since September against areas in Iraq and Syria taken over by ISIS in the past year. 

Experts estimate that ISIS's revenue from oil sales stands at more than $1 million per day. The oil facilities are being specifically targeted by coalition airstrikes.

In addition to targeting ISIS facilities in Raqqa, the coalition also launched airstrikes on Sunday against military bases of the Al Nusra Front, an al Qaeda affiliate, in Atmeh. The Syrian Observatory said nine members of the Al Nusra Front were killed in the attack.

Al Nusra Front earlier declined to join the Islamic State under al-Baghdadi and chose instead to align itself with al Qaeda. The two groups reportedly clashed on February 23 on the outskirts of Lebanon's Ras Baalbek, leading to the arrest of Abu Hareth al-Ansari by Lebanese authorities in Hasbaya, west Bekaa.

Al-Hansari is a Syrian commander of an Al Nusra Front unit, and was undergoing treatment for wounds sustained during the fighting in Hasbaya's Al-Manar Hospital when he was arrested Monday last week.

Although Lebanese authorities refer to al-Hansari as an ISIS commander, a Daily Star source denied this.