Israeli strikes on Monday hit a power supply system in the Iranian capital, triggering outages in some areas around the city, Iranian media reported.

The power distribution line in northern Tehran "was damaged, causing outages in some areas", Fars news agency reported.

Israel carried out a fresh strike on Iran's underground Fordo nuclear site south of Tehran, a media outlet in the country reported.

"The aggressor attacked the Fordo nuclear site again," Tasnim news agency reported, quoting a spokesperson for the crisis management authority in Qom province where the site is located.

Shortly after U.S. B-2 bombers began their return to the U.S. after they struck Iran’s key nuclear facilities, U.S. President Donald Trump called Israeli Prime Minister Benjamin Netanyahu to brief him on the strike, U.S. and Israeli officials told U.S. news portal Axios.

Iran said Monday the attacks launched on the Islamic republic during talks about its nuclear program were a "betrayal of diplomacy".

"We and future generations will not forget that the Iranians were in the middle of a diplomatic process with a country that is now at war with us," said foreign ministry spokesman Esmaeil Baqaei.

Sirens wailed across Israel for over 30 minutes on Monday and loud explosions were heard in Jerusalem on Monday, as the military warned of multiple missile barrages launched from arch-foe Iran.

After the extended alert period in several areas of the country, the Israeli military later said civilians could leave shelters.

The United Nations special envoy for Syria denounced Sunday's attack on a church in Damascus that killed at least 20 people as a "heinous crime".

Prime Minister Benjamin Netanyahu said Sunday that his promise to destroy Iran's nuclear facilities had been "fulfilled" following strikes carried out "in perfect coordination" between the Israeli and U.S. militaries.

Iran's Foreign Minister Abbas Araghchi on Sunday condemned US attacks on key nuclear sites as "outrageous" and said his country has a right to defend its sovereignty.

"The events this morning are outrageous and will have everlasting consequences," he posted on X, adding that the attacks were "lawless and criminal" behaviour.

The U.N.'s International Atomic Energy Agency (IAEA) on Sunday said that it had not detected any increase in radiation levels at key nuclear sites in Iran following U.S. air strikes.

The Israeli military said it launched a fresh series of strikes Sunday targeting military targets including missile launchers in western Iran after the United States attacked the country's nuclear sites.