President Donald Trump urged civilians living in Tehran to evacuate the Iranian capital "before there is nothing left."

Israel appeared to be expanding its air campaign on Tehran five days after its surprise attack on Iran’s military and nuclear program, as U.S. President Donald Trump posted an ominous message warning residents of the capital to evacuate.

The Israeli military said Monday that it can now fly over the country's capital, Tehran, without facing major resistance after crippling Iran’s air defenses in recent strikes, enabling Israel to hit an expanding range of targets with relative ease.

The president’s ominous evacuation warning came hours after the Israeli military told residents in some parts of Tehran to leave as it struck a state television complex in the city.

"Iran should have signed the 'deal' I told them to sign," the president wrote. "What a shame, and waste of human life."

Israel also targets the headquarters of Iran's Defense Ministry • Defense Minister Israel Katz: "Tehran is ablaze"

That came as fresh attacks targeted Iran's energy infrastructure, including fuel supplies and a top natural gas field.

DUBAI (Reuters) -Air defences in Iran's capital Tehran were activated early on Saturday to intercept fresh Israeli strikes, state media IRNA reported a day after Israel initiated a number of attacks on Iran's nuclear programme and military command.