Sirens blared as David Letterman interviewed Volodymyr Zelensky 300ft underground in a subway station in Kyiv.

The television host travelled to the Ukrainian capital to interview the country's president for a new Netflix special, My Next Guest with David Letterman and Volodymyr Zelenskyy, which premiered on 12 December.

The host said he was "reassured" to be with Zelensky as the alarm rang out.

The siren means that "war has become a habit," Zelensky told Letterman.

"Many Ukrainians have gotten used to it... war shouldn't be a habit," he added.