Full statement by the Haines family following the beheading of David Haines by Islamic State militants in Syria.
A propaganda video showing the execution of kidnapped British aid worker David Haines by a militant from the Islamic States (formerly ISIS) has appeared on YouTube and other video sharing sites.
The US has negotiated support from ten Arab states to help them tackle the threat of the Islamic State (formerly ISIS) in Iraq, Syria, and elsewhere.
Hassan Abboud and around 20 other top commanders from the Islamist rebel group Ahrar Ash Sham have been killed in a suicide bomb blast.
The US has confirmed that video showing the killing of reporter Steven Sotloff is authentic, but said they will not be intimidated by the barbarism for the militant group.