(http://news.bbcimg.co.uk/media/images/75306000/jpg/_75306515_line976.jpg)
Who are Boko Haram?(http://news.bbcimg.co.uk/media/images/75329000/jpg/_75329061_nigeriamaidugurigwozamandara4640614.jpg)
- Founded in 2002
- Initially focused on opposing Western education - Boko Haram means "Western education is forbidden" in the Hausa language
- Launched military operations in 2009 to create an Islamic state
- Thousands killed, mostly in north-eastern Nigeria - but also attacks on police and UN headquarters in capital, Abuja
- Some three million people affected
- Declared terrorist group by US in 2013
Who are Boko Haram? (http://www.theinfostride.com/news/world-africa-13809501)
Profile: Boko Haram leader Abubakar Shekau (http://www.theinfostride.com/news/world-africa-18020349)
(http://news.bbcimg.co.uk/media/images/75306000/jpg/_75306515_line976.jpg) In his previous video, released in July, Mr Shekau congratulated the Islamic State (IS) for its advances in Iraq and Syria but did not say whether they were allies - there is no evidence that the two groups have been working together.
IS has seized much of northern Iraq in recent months, leading the US to launch air strikes.
Last week, the militants sparked global outrage by beheading US journalist James Foley.
(http://news.bbcimg.co.uk/media/images/75306000/jpg/_75306515_line976.jpg) Syria, Iraq and Islamic State The rise of Islamic State (http://www.theinfostride.com/news/world-middle-east-28116033)
Analysis: Nature of IS threat (http://www.theinfostride.com/news/world-middle-east-28896348)
(http://news.bbcimg.co.uk/media/images/75306000/jpg/_75306515_line976.jpg) Gwoza is not far from Chibok, where Boko Haram kidnapped more than 200 schoolgirls in April.
Nigeria's police say it is still looking for 35 police officers who went missing after Boko Haram attacked a police academy in Liman Kara, near Gwoza last week.
Residents say the militants seized the college but it is unclear who now controls it.
Nigeria declared a state of emergency in three north-eastern states in 2013 but the insurgency has continued and even intensified.
Source: BBC