Thousands of people were fleeing Tehran on Wednesday after Israeli warplanes bombed the city overnight, and a source said U.S. President Donald Trump was considering options that include joining Israel in attacking Iranian nuclear sites.

Explosions were heard in Tehran early Wednesday as Israeli warplanes pounded Iran’s capital overnight and into Wednesday. Iran’s supreme leader on Wednesday rejected U.S. calls for surrender and warned that any military involvement by the Americans would cause “irreparable damage” to them.

Israel's military said it was striking military targets in Tehran in its latest salvo against the Iranian capital, after issuing evacuation warnings for one neighborhood. The military said it would publish more details as the situation progresses.