Revolutionary Guard members patrolled the city on motorbikes, and plainclothes security men were also out in force. People looked down as they walked briskly past police, apparently trying not to draw attention to themselves.
Donald Trump tweeted several messages about Iran over the weekend, including one in Farsi warning Iranian leaders dont kill your protesters.
Ali Rabiei, the government spokesman, accused Mr Trump of shedding crocodile tears and said the US president did not really care about the lives of Iranians.
Mr Trump only deepened confusion over his strategy towards Iran as he openly contradicted his national security advisors claim that US sanctions would force Tehran to return to the negotiating table over the nuclear deal.
Actually, I couldnt care less if they negotiate. Will be totally up to them but, no nuclear weapons and dont kill your protesters, he wrote on Twitter.