A shadowy jihadist group believed to be linked to al-Qaeda fought alongside rebels who seized a government missile defence base in Syria yesterday, activists said.
The claim heightens fears extremists are taking advantage of the chaos to acquire advanced weapons.
Videos posted online said to have been shot inside the base said the group, Jabhat al-Nusra, participated in the overnight battle for the air defence base near the village of Taaneh, east of Aleppo in northern Syria. The videos show dozens of fighters inside the base near a radar tower, along with rows of missiles, some on the backs of trucks.
A report by a correspondent with the Arabic satellite network Al-Jazeera who visited the base said Jabhat al-Nusra had seized the base.
Little is known about Jabhat al-Nusra, or the Support Front, which began claiming attacks in Syria earlier this year in postings on jihadist forums often used by al-Qaeda. While neither group has officially acknowledged the other, analysts say al-Nusra's tactics, jihadist rhetoric and use of al-Qaeda forums point to an affiliation.
Western powers - and many Syrians - worry that Islamist extremists are playing an increasing role in Syria's civil war, which started in March last year as a mostly peaceful uprising against President Bashar al-Assad.
Despite their opposition to the Assad regime, the United States and others have cited the presence of extremists among the rebels as a reason not to supply them with weapons. Rebel leaders say the lack of military aid leaves a vacuum that extremists can exploit.
The capture came a day after Turkey claimed to have seized ammunition and military equipment from a plane it intercepted from Moscow to Syria.
However, Syria accused Turkey's Prime Minister Recep Tayyip Erdogan of "lying" about the presence of arms on board.
"The Turkish prime minister continues to lie in order to justify his government's hostile attitude towards Syria," the Syrian foreign ministry said.
The information ministry challenged Erdogan to show the alleged weapons seized.
Additional reporting by Agence France-Presse