Hundreds of protesters have now been killed in an escalating government crackdown in Iran, BBC sources and activists report. Thousands more are said to have been arrested.
US President Donald Trump has repeatedly threatened military action on Iran if security forces kill protesters.
The BBC’s Paul Adams looks at what Trump has said about the US response and what it could mean.
More Stories
Can the U.S. wrest Strait of Hormuz from Iran, a regional military power? – National
Kid Rock sparks US Army probe after helicopter flyby at his mansion
Kid Rock sparks US Army probe after helicopter flyby at his mansion