The death toll from Israeli strikes in northwestern Iran on Friday increased to 18, state media reported, revising an earlier figure of eight dead.

"So far, as a result of this brutal aggression, 18 individuals have attained martyrdom and 35 of our fellow citizens have been injured," state news agency IRNA quoted East Azerbaijan provincial authorities as saying.

Several explosions were heard in Tehran and surrounding areas Friday evening, 12 hours after a massive wave of Israeli attacks on the country. "There were reports of explosions heard in the west of Tehran province," in the cities of Shahriar and Malard and around the neighbourhood of Chitgar in Tehran city, according to IRNA, while Mehr agency reported a blast in Pakdasht, southeast of the capital.

Israel's national security advisor, Tzachi Hanegbi, said that the country has no plans to kill Iran's leaders. He also added that it was "impossible" to destroy Iran's nuclear programme using only force.

"It is impossible to destroy the nuclear programme with force alone. The goal is to make the Iranians understand that they will have to stop the nuclear programme," Hanegbi said on Israel's Channel 12. However, the Israeli military chief said that it will use full force to achieve its goals after Iran strikes.

Meanwhile, the newly appointed commander of Iran's Islamic Revolutionary Guard Corps, Mohammad Pakpour, threatened to open "the gates of hell" in retaliation for Israel's attacks that killed his predecessor, Hossein Salami. "In retribution for the blood of our fallen commanders, scientists and citizens, the gates of hell will soon be opened upon this child-killing regime," Pakpour said of Israel in a message carried by IRNA.