In an exclusive interview with AFP on the sidelines of a European summit in Britain, NATO Secretary General Jens Stoltenberg says it is "extremely important" that the United States maintains its backing for Ukraine, after former president Donald Trump chose J.D.Vance, a sceptic of aiding Kyiv, as his running mate. "This has to be a joint effort between North America and Europe, and the United States is by far the biggest ally. So, I expect them to continue to support Ukraine," he says. EXCLUSIVE IMAGES AND SOUNDBITES