As the US weighs joining Israel’s assault on Iran, questions are mounting over whether such an intervention could trigger regime change in Tehran – an outcome that risks splintering the country and sending shockwaves across the region.

For Iran, U.S. citizens are urged not to travel there for any reason and "should depart Iran immediately if they are there". "U.S. citizens who are unable to depart Iran should be prepared to shelter in place for extended periods," the State Department said.

People assembled in Tehran on Friday (June 20) for a rally against Israel, burning Israeli and American flags, displaying photographs of slain leaders, and chanting anti-Israel slogans. Putin says he does not want to discuss possible killing of Iran's Khamanei What are rare earth elements and why are they important?