US President Donald Trump has warned Iran against using lethal force on protesters, stating the US would intervene and "hit them very hard where it hurts" if demonstrators are killed. Trump described Iran as being in "big trouble" with widespread unrest, suggesting the people were taking over cities. He emphasized that any US response would not involve ground troops. Meanwhile, Iran's Supreme Leader Ayatollah Ali Khamenei dismissed Trump's remarks, accusing him of being stained by Iranian blood, as state media labeled protesters as terrorists.