New Delhi, March 19 -- Iran and Russia both allege that a projectile struck the grounds of the Bushehr nuclear power plant in the Islamic Republic, raising the specter of a radiological incident as Tehran's war with Israel and the United States rages.

And though no release of nuclear material was reported following the incident on Tuesday evening, it again underlines a longtime worry of Iran's neighbors - that the power plant on the shores of the Persian Gulf could be hit by either an attack or a natural disaster such as an earthquake.

Here's what to know about the incident, the plant itself and Iran's wider nuclear program - which U.S. President Donald Trump points to as one of the reasons for starting the war alongside Israel against ...