BEIRUT: Rebels led by Al-Qaeda-linked fighters seized Syria’s largest oilfield on Saturday, cutting off President Bashar Assad’s access to almost all local crude reserves, activists said.

There was no immediate comment from the government and it was not possible to verify the reports of the capture independently.

But the loss of the Al-Omar oil field in the eastern Deir El-Zor province, if confirmed, could leave Assad’s forces almost completely reliant on imported oil in their highly mechanized military campaign to put down a 2-1/2-year uprising.

“Now, nearly all of Syria’s usable oil reserves are in the hands of the Nusra Front and other Islamic units ... The regime’s neck is now in Nusra’s hands,” said Rami Abdelrahman, head of the pro-opposition Syrian Observatory for Human Rights.

In the northern province of Aleppo on Saturday, army air strikes killed at least 40 people and wounded dozens, most of them civilians, the Observatory said.

But opposition fighters, particularly powerful Islamic factions, still hold large swathes of territory in northern and eastern Syria.

Foreign powers are trying to bring together the warring parties at an international peace conference, dubbed ‘Geneva 2’, planned for mid-December. Both the Syrians and their international partners are at odds over terms for the talks.

Syria’s peace envoy Lakhdar Brahimi discussed the conference on Saturday with Russian Foreign Minister Sergei Lavrov in Geneva. He is expected to meet US Secretary of State John Kerry later.

Most oil reserves are now in the hands of rebels, local tribes or Kurdish militias, some of whom may be willing to sell oil to Assad.

Assad is also believed to be getting fuel from Iran, his main regional ally.

A video posted on the Internet showed rebels in camouflage and black scarves driving a tank under a sign that read “Euphrates Oil Company — Al-Omar field.”

The speaker in the video said the field was overrun at dawn on Saturday, but the authenticity of the footage could not be independently verified.