LONDON — A British hostage of the Islamic State has been shown in a video, apparently made in the beleaguered Syrian town of Kobani near the Turkish border, depicting him as a combat correspondent and forecasting that the town is about to fall to militants despite waves of American airstrikes.

The video, about five and a half minutes long, suggests a further evolution in the militants’ command of media technology to promote their cause, using the techniques of 24-hour news channel journalism to counter the West’s accounts of what is happening in Kobani.

Punctuated by the rattle of machine-gun fire, the clip begins with aerial views of the town, apparently a further indication of the militants’ use of surveillance drones.

“Hello, I’m John Cantlie,” the hostage says, dressed in black, “and today we are in the city of Kobani on the Syrian-Turkish border. That is, in fact, Turkey right behind me.”