Israel is closely monitoring the fallout from widespread Iranian protests. An Israeli official said Sunday that U.S.

Iran has warned it will retaliate if it is attacked by the US, as protesters defied a government crackdown on Saturday night despite medics at two hospitals telling the BBC more than 100 bodies had been brought in over a two day period.

Republican Sen. Rand Paul warned about the unintended consequences of U.S. military intervention in Iran on Sunday.

For a third night in a row, nationwide antigovernment protests rocked Iran, according to witnesses and videos verified by The New York Times, posted on BBC Persian and social media, even as the government intensified its crackdown and the military said it would take to the streets in response to the unrest.

The protests, which started out with economic grievances, have now morphed into one of the biggest challenges the Islamic Republic has faced in its 47-year history.

Israeli Prime Minister Benjamin Netanyahu and U.S. Secretary of State Marco Rubio spoke as Israel goes on high alert and Iran faces mounting anti-regime protests.

U.S. President Donald Trump has threatened to attack Tehran "very hard where it hurts" if authorities kill protesters in Iran.