**PARIS: Iran on Wednesday vowed fast-track trials for people arrested over a massive wave of protests, after US President Donald Trump threatened “very strong action” if the Islamic republic goes ahead with hangings.**In Tehran, authorities held a funeral ceremony for over 100 members of the security forces and other “martyrs” killed in the demonstrations, which authorities have branded as “riots” while accusing protesters of waging “acts of terror”. The protest movement across Iran, initially sparked by economic grievances, has turned into one of the biggest challenges yet to the clerical leadership since it took power in 1979. Demonstrators have defied the authorities’ zero-tolerance for dissent by turning out in protests all around the country, even as authorities insist they have regained the upper hand. Iran’s judiciary chief Gholamhossein Mohseni Ejei said on a visit to a prison holding protest detainees that “if a person burned someone, beheaded someone and set them on fire then we must do our work quickly”, in comments broadcast by state television. Iranian news agencies also quoted him as saying the trials should be held in public and said he had spent five hours in a prison in Tehran to examine the cases. Footage broadcast by state media showed the judiciary chief seated before an Iranian flag in a large, ornate room in the prison, interrogating a prisoner himself. The detainee, dressed in grey clothing and his face blurred, is accused of taking Molotov cocktails to a park in Tehran. Trump on Tuesday said in a CBS News interview that the United States would act if Iran began hanging protesters. “We will take very strong action if they do such a thing,” said the American leader, who has repeatedly threatened Iran with military intervention. “When they start killing thousands of people — and now you’re telling me about hanging. We’ll see how that’s going to work out for them,” Trump said.