Israel unleashed airstrikes across Iran for a third day and threatened even greater force as some Iranian missiles evaded Israeli air defenses to strike buildings in the heart of the country.

Sirens sounded in Israel as Iran launched dozens of ballistic missiles in retaliation for Israel's strikes on its nuclear facilities.

Explosions have been seen over Tel Aviv and Jerusalem as the country faces yet another barrage of missiles from Iran. It comes after explosions were reported in central Tehran, as attacks continue between Iran and Israel.

The fighting, which began on Friday with a surprise Israeli attack on Iran, has been some of the fiercest and most prolonged in the decades-long enmity between Israel and Iran, raising fears of a wider war that could draw in the United States and other powers.

Iran has fired two waves of missiles into Israel overnight. Another set of strikes near Tel Aviv killed a 60-year-old woman, according to the Israeli emergency service Magen David Adom (MDA). A further 20 people have been injured in the same area, as well as 24 people in the Judean Foothills, a spokesperson for the MDA added.

Missiles and projectiles were seen in the skies over Jerusalem and Tel Aviv early on Sunday as Tehran unleashed a fresh attack on Israel which in turn launched an expanded assault on Iran.

Israeli citizens were ordered to head to bomb shelters on Friday night amid retaliatory missile strikes from Iran.