Internet access has been reduced or effectively cut off in parts of Iran since Saturday night, particularly in areas where protests have been more intense, according to messages received by Iran International.
The number of messages sent from inside Iran declined noticeably from Sunday afternoon, suggesting broader disruptions.
Users who were able to communicate from areas under restrictions reported spending hours trying to send even a single text message.
A resident of the western Iranian city of Asadabad said internet access in the city, where protests have been strong, was effectively cut off, preventing video uploads and making text messaging difficult
Similar accounts were received from several other cities, including Kermanshah, Dezful, Malekshahi, Malard, Marvdasht, Kuhdasht, Borazjan, Mashhad, Shiraz, and parts of Tehran.
A key feature of the restrictions appears to be their regional application, with areas experiencing higher levels of protest activity facing tighter internet limitations, including in Tehran where districts with more protests have seen more severe disruptions.