It remained to be seen whether the attack would ignite a regional war or provide the U.S. and Iran with an off-ramp from their intensifying confrontation.

Iran’s foreign minister Abbas Araghchi is preparing to meet Russian President Vladimir Putin, saying he expected their conversation to “be in the interests of both countries”. Araghchi said late on Sunday night that he would have “serious and important discussions” with Putin in Moscow.

Israel targeted Evin prison in Tehran on Monday, one of the most potent symbols of Iran's governing system, in what Israel called the most intense bombing yet of the Iranian capital, a day after the United States joined the war by blasting nuclear sites.