US President Donald Trump has warned that “very strong action” could follow if Iranian authorities carry out threatened executions of protesters, as international outrage continues to grow over a crackdown that rights groups say has killed thousands. While France 24 has been unable to independently verify the death toll, the unrest represents one of the most serious challenges yet to Iran’s clerical leadership. Tehran has dismissed the US warnings as a “pretext for military intervention.” Fraser Jackson reports from Washington.