Harrowing, riveting, essential: 20 Days in Mariupol is a visceral addition to the roster of frontline documentary-making. But unlike films such as Restrepo and Armadillo, both of which were captured by directors embedded over an extended period with battalions of soldiers (in both cases in Afghanistan), 20 Days… plays out among civilians. Ukrainian journalists working for the Associated Press, among them first-time director Mstyslav Chernov, are on the ground in the strategically important port city of Mariupol at the start of the Russian invasion. Their unflinching lenses capture the sickening collective realisation that ordinary people are now targets. This is a film about an accelerating conflict. It’s also a about journalists under extreme duress, scouring a wrecked city for a wifi signal to make the world aware; about the grave spiritual toll that comes from bearing witness.

A sobering narration from Chernov describes the circumstances behind footage showing grey-faced medics attempting to resuscitate injured babies; the shattered despair of parents whose children have been shelled while playing football. There’s something deadened and almost matter-of-fact in Chernov’s voiceover, his numbed delivery in stark contrast to the frantic urgency of the images on screen. The camera rolls at all times, even when members of the press are dodging sniper bullets and aerial bombardment. Doctors break off during emergency surgery to urge Chernov and his colleagues to film the casualties. The world needs to see, says one. But you also get the sense that perhaps Chernov needed someone else to share the unimaginable burden of knowledge and grief. It’s an extremely tough watch, but an important one.