Media playback is unsupported on your device

Syria conflict: Who are ISIS?

9 January 2014 Last updated at 10:15 GMT

Recent days have seen fierce fighting between the al-Qaeda-affiliated Islamic State in Iraq and the Levant (ISIS) and other rebel groups in Syria.

On Thursday, Islamist rebels captured the ISIS headquarters in Aleppo.

More than 270 people, including 46 civilians, have been killed in the worst rebel-on-rebel violence since the uprising in Syria began in March 2011, according to the Syrian Observatory, a UK-based activist group.

James Reynolds reports from the Turkey-Syria border on Syria's "second war".

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.