UN humanitarian chief Tom Fletcher has warned that the war in Iran and wider region is having a "massive impact" on civilians, describing it as "a moment of grave, grave peril".

He also voiced concerns about "secondary impacts" of the violence, saying the conflict risked fuelling an increase in extremism and polarisation in the Middle East and beyond.

"We've got to step back from the brink right now", he told the BBC's Laura Kuenssberg.