Israel’s unprecedented attacks on Iran had at their core an elusive and high-risk goal: eradicating the country’s controversial nuclear program.

Israel warned hundreds of thousands of Tehran residents to evacuate a central district of the Iranian capital Monday, as the assault it began last week continued for a fourth day. Iranian strikes also targeted Tel Aviv and other major cities.

The head of the International Atomic Energy Agency says there is a possibility of both radiological and chemical contamination within Iran’s main nuclear enrichment facility in Natanz.

Only the U.S. military has the 30,000-pound bomb capable of reaching the facility and the bomber that can carry it.

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.

Israel says it first bombed Iran to stop it from being able to produce nuclear weapons and the “existential threat” they would represent.

Explosions rang out across Iran’s capital as Israel claimed it was attacking the country. People in Tehran, Iran, awoke to the sound of the

Explosions reported in capital Tehran as Israeli Defence Minister announces "pre-emptive strikes" and announces state of emergency