BEIRUT: An air raid has struck several cars in northwestern Syria, killing at least eight people, including al-Qaida-linked fighters and a senior commander with a Chinese Islamic militant faction, an activist group and a local jihadi commander said Monday.

The attack occurred late Sunday on a road leading from the town of Sarmada to the Bab al-Hawa area on the border with Turkey, said the Britain-based Syrian Observatory for Human Rights and a local commander with the Fatah al-Sham Front, an al-Qaida-linked group. The militant spoke via text messages on condition of anonymity because of security concerns.

It was not immediately clear who was behind the attack, but the Observatory's chief Rami Abdurrahman said it is widely believed to have been carried out by the US-led coalition.

The US has killed some of al-Qaida's most senior commanders in Syria over the past two years in airstrikes. Those targeted included members of the so-called Khorasan group, which Washington describes as an internal branch of al-Qaida that plans attacks against Western interests.

The Observatory said eight people were killed in the airstrike, including three jihadi commanders. The dead include a senior al-Qaida commander known as Khattab al-Qahtani, who was from the Gulf region and fought for the group in Afghanistan.

Abu Omar al-Turkistani, a top commander with the Turkistan Islamic Party, and a Syrian al-Qaida commander known as Abu Muatasem al-Deiri, were also killed. The Turkistan Islamic Party mainly consists of minority Uighurs from China, many of whom have traveled to Syria to help battle President Bashar Assad's forces alongside other jihadi groups.

The Fatah al-Sham commander confirmed that several people were killed, including al-Qahtani and al-Turkistani. He said the attack was most likely carried out by drones.

A video posted online by the Syrian Civil Defense search-and-rescue group, also known as the White Helmets, showed rescue workers spraying a car with fire extinguishers as a body was removed and placed in a black bag. The video appeared genuine and corresponded to other Associated Press reporting.

Earlier Monday, Syria's state news agency said al-Qaida militants knocked out electricity towers near the capital, causing power cuts in a southern province. SANA said Fatah al-Sham fighters bombed three towers southwest of Damascus, causing electricity cuts in the Quneitra region.

The report came as a cease-fire brokered by Russia and Turkey held for the fourth day amid sporadic violations. Fighting has raged in the water-rich Barada Valley northwest of Damascus over the past two weeks.

The Fatah al-Sham Front, previously known as the Nusra Front, and the Islamic State group are not included in the truce.