Britain verifying video of aid worker's beheading by ISIS

London: The UK foreign office said on Saturday it was "working urgently to verify" a video purporting to show beheading of a British hostage by the Sunni militant group Islamic State (IS) in Syria, media reported.

The foreign office said that it was trying to confirm the authenticity of the video purporting to show the death of aid worker David Haines, who was kidnapped last year in Syria, Xinhua reported.

If true it was another "disgusting murder", the foreign office said, adding that it was offering support to Haines' family.

IS group, running amok in Syria and Iraq, has already beheaded two US journalists and had threatened to kill Haines if US airstrikes in Iraq were not halted.