Al-Qaeda's Syrian affiliate the Nusra Front launched an offensive Friday on the headquarters of a new US-formed rebel group in the country's north, leaving at least 11 dead, a monitor said.
The attack came one day after Nusra kidnapped eight rebels from Division 30, who had been trained and equipped by Washington, the Syrian Observatory for Human Rights monitoring group said.
"Nusra attacked at dawn the headquarters of Division 30, near the town of Azaz in the northern province of Aleppo," the Britain-based Observatory said.
Clashes broke out after the assault, which killed five Nusra fighters and allied militants and six rebels who were defending Division 30, observatory director Rami Abdel Rahman said.
| At least 54 members of Division 30 entered Syria in mid-July, equipped with 30 US-made all-terrain vehicles, arms, and ammunition. |
He said Nusra launched the attack to seize weapons "given by Washington to the rebels" but that the group had not been able to enter the base as fighting was ongoing.
In a statement posted on its Facebook page about the attack, Division 30 called on Nusra to stop "spilling the blood of Muslims".
At least 54 members of Division 30 entered Syria in mid-July, equipped with 30 US-made all-terrain vehicles, arms, and ammunition.
Eight of them, including a commander, were kidnapped on Thursday by Nusra in a village in Aleppo province, the observatory said.
Division 30 denounced the kidnapping of Colonel Nadim Hassan and his companions, demanding "the brothers of Nusra Front liberate them immediately".
A spokeswoman for the US Department of Defense denied the kidnapping.
"I can confirm that there have been no New Syrian Force personnel captured or detained," said Commander Elisa Smith.
Are US forces in Syria?
The "New Syrian Force" is the term used by Washington to describe the Syrian rebels screened to exclude extremist elements and who have completed a training course led by US troops.
One FSA commander who claimed to have been trained by the US and gave his name as Mohammed told US broadcaster PBS that he had seen US personnel inside Syria calling in airstrikes against the Islamic State group (IS).
The US has stated it will not send ground troops into Syria, relying instead on local proxies.
More than 230,000 people have been killed in Syria since the conflict began in March 2011 with anti-government protests that descended into a civil war after a regime crackdown.