Iran and Israel traded air and missile strikes as the world braced on Monday for Tehran's response to the U.S. attack on its nuclear sites and U.S. President Donald Trump raised the idea of regime change in the Islamic republic, Reuters reported.

Iran vowed to defend itself on Sunday, a day after the U.S. joined Israel in the biggest Western military action against the country since its 1979 Islamic Revolution, despite calls for restraint and a return to diplomacy from around the world.

Commercial satellite imagery indicated the U.S. attack on Saturday on Iran’s subterranean Fordow nuclear plant severely damaged or destroyed the deeply buried site and the uranium-enriching centrifuges it housed, but the status of the site remained unconfirmed, experts said, according to Reuters.

In his latest social media comments on the U.S. strikes, Trump said "Monumental Damage was done to all Nuclear sites in Iran."