"There is no nightlife allowed. We have notified businesses that they should close by 1 a.m." said Tehran Police Chief Hassan Rahimi to reporters on Monday.
Tehran City Councillor Zahra Nejad Bahram had said earlier on Monday that police had agreed in coordination with the city council to allow some businesses in designated areas to remain open for residents' nightlife.
Nightlife in Tehran consists of a few restaurants, coffee shops and tea houses which stay open until 3 a.m.
Iranian police and "hijab patrols" have been increasingly targeting parties and other social gatherings recently, according to Radio Farda.
On social media, some Iranians argued that generally when the government makes life harder for ordinary citizens, it's probably compromising on some international issues.
On Saturday, Rahimi announced that 547 "luxury" restaurants and cafes were closed and sealed in Tehran and 11 people were arrested during the last ten days of Ramadan.
"Unconventional advertising” and the use banned music for the entertainment of customers were the stated reasons behind the closures, according to Radio Farda.
During Ramadan, all restaurants in Iran are closed from the early morning until the evening when fasting ends. This year's policy implies a tougher policy was applied.
Radio Farda reported that similar closures occurred in other Iranian cities. Individuals who eat or drink in public during the fast are arrested, flogged or jailed. The act is not legally prohibited in Iran, but judges convict people who eat in public during the fast under a law banning any "haram" (religiously-prohibited) act in public.