Internet services have been disrupted in parts of Iran amid reports it is being cut off ahead of planned anti-government protests on Thursday.
Semi-official Iranian news agency Ilna quoted an unnamed official as saying the action had been officially ordered.
It comes amid calls for demonstrations in memory of those killed in protests fuelled by price rises last month.
Amnesty International says at least 304 people were killed and thousands arrested during a days-long crackdown by security forces. Reuters news agency put the death toll at about 1,500, based on information from unnamed interior ministry officials.