President Donald Trump says the strikes "totally obliterated" Iran's nuclear enrichment facilities and told Tehran to "make peace" or face "far greater" attacks in future.
In response Iran's foreign minister warned of "everlasting consequences" to the "outrageous" strikes.
The UN's nuclear watchdog says no increase in radiation levels has been detected.
The UK was not involved in the US strikes but was told about them in advance, the BBC understands.
