Iran is ready to retaliate against the Israeli "aggression," Iran's semi-official Tasnim news agency said Saturday, citing sources.
"There is no doubt that Israel will receive the appropriate response to any action it takes," the sources were quoted.
It came after Israel announced early Saturday that its military conducted "precise strikes" against "military targets" in Iran, as explosions were heard in the Iranian capital of Tehran.
Iranian media reported the sound of five new explosions in Tehran, as Israel began a second wave of attacks against the country.
Tasnim confirmed that air defense systems in central Tehran have been activated in response to the escalating attacks.
Meanwhile, Iran's Civil Aviation Organization announced that flights on all routes have been cancelled "until further notice."
The US said that Israel "is conducting targeted strikes against military targets in Iran as an exercise of self-defense and in response to Iran's ballistic missile attack against Israel on October 1st."
The White House confirmed that President Joe Biden and Vice President Kamala Harris were briefed on the strikes.
"The US was informed beforehand and there is no US involvement," according to a defense official.
Separately, Syrian news agency Sana said explosions were also heard in the capital of Damascus.
There has been no further information disclosed.
Israel's state television, KAN, reported that Prime Minister Benjamin Netanyahu and Defense Minister Yoav Gallant were at the Defense Ministry building during the strikes.
