The strikes unleashed toxic black smoke from raging fires, blocking out the sun and enveloping the city in a dense cloud on Sunday morning.

Iranians in the capital tell the BBC of "constant explosions", as the US warned attacks will intensify.

TEHRAN: For a moment Tehran resembled a city at peace, with birdsong, joggers and tranquil views of the snow-capped Alborz mountains in the distance. Then the sound of another…