20 November 2013 Last updated at 22:31 GMT
A British man in Syria has told the BBC he is fighting for a group linked to al-Qaeda.
Ifthekar Jaman, 23, from Southsea, Hampshire, told Newsnight the Islamic State in Iraq and the Levant (ISIS) was engaged in a jihad to establish a state based on Islamic religious law.
"I am ISIS. This is the group I am with. We are trying to establish the law of God, the law of Allah," he said.
Mr Jaman, whose family come from Bangladesh, is believed to have left the UK in spring of this year. His exact location inside Syria is unclear.
Newsnight managed to speak to him via an internet video call, with the help of his brother in the UK.
Refugees from the Syrian city of Raqqa report that since ISIS took control there, activists have been beaten, the sale of alcohol has been banned and women made to wear Islamic dress.
See more from Richard Watson on Newsnight on the BBC iPlayer and the Newsnight website.