The BBC has issued a statement in response to the release of a video showing kidnapped journalist Alan Johnston.

"We are studying the video very carefully," the corporation said. "We have been working very closely with Alan's family for the past 81 days. This is a highly distressing time for them and for his friends and his colleagues. We repeat our call for his immediate release."

The video was sent to the Palestinian news service Ramattan before being released on the internet.