(Reuters) - Turkey has closed one of its border gates to Syria after an al Qaeda-affiliated rebel group clashed with units of the Arab- and Western-backed Free Syrian Army in the Syrian town of Azaz near the Turkish frontier, a Turkish official said on Thursday.

"The Oncupinar border gate has been closed for security reasons as there is still confusion about what is happening on the Syrian side. All humanitarian assistance that normally goes through the gate has ceased," the official told Reuters.