Tensions are high over the possibility Iran will retaliate for an air strike that killed senior Iranian commanders nearly two weeks ago.

US officials had told CBS News, the BBC’s US partner, that a major attack on Israel could happen imminently.

Israel has said it is ready “defensively and offensively”.

“I can’t speak to the size, scale, scope of what that attack might look like,” US National Security Council spokesman John Kirby said on Friday. But he added that the Iranian threat was “viable,” saying Washington was “watching this very, very closely”.

He said: “We are in constant communication with our Israeli counterparts about making sure that they can defend themselves against those kinds of attacks”.