Security forces have deployed in the Iranian city of Esfahan on Thursday after government agents attacked protesting farmers in their camp earlier in the day.

Reports and social media videos from Esfahan show that special riot police armored cars are visible throughout the city and some streets have been closed to traffic. Farmers and Esfahan residents have called for a large protest on Friday.

A large protest of tens of thousands of people took place last Friday in the city center, where people gathered on the dry riverbed of Zayandeh Roud, Esfahan’s iconic river, which has been dry for most of the last decade because of draught and water diversion by the government.

Farmers and residents demand water to flow again and the river come back to life, providing much-needed irrigation for communities around the historic city.

Early Thursday, plainclothesmen and security forces attacked a makeshift camp set up by farmers two weeks ago on the dry riverbed. They destroyed and set fire to the farmers’ tents and arrested many protesters. They also brought heavy machinery to cleanse the scene of any signs of the camp and the fire.

Residents reported a heavy presence of security forces Thursday afternoon, possibly in preparation to intervene on Friday to prevent a larger gathering.

Internet connection has also been disrupted in the city center, usually a sign of possible crackdown as authorities do not want images to be published online showing force being used against citizens.

Some reports say security forces arrested around 50 farmers, but government media says most were released later.

The political deputy of Esfahan’s governor claimed that security forces did not use any force against the camping farmers, and they were simply dissuaded through “conversation” to disperse. He said that from now on, any protest would be involving “troublemakers” and “not related to farmers”.

His remarks could be another sign of authorities preparing to crackdown if residents of the city congregate on Friday.

Until a few days ago, the government tried to show that it tolerates protests to water scarcity and argued that farmers and citizens had a valid grievance, which was not political. The interior minister Ahamd Vahidi, however, said Thursday that water protests were an attempt “by the enemy to sow discord”, and the Islamic Republic should allow repeat of any protests.

The sudden change in tone could be related to the passing of an important anniversary. November 15 marked the second anniversary of the 2019 anti-regime protests when security forces killed hundreds of unarmed demonstrators across the country. The government probably did not want a repeat of violence to coincide with a sensitive date, which could fuel unrest in other parts of the country.

Social media users reported that many people received text messages from security agencies warning them not to show up at any protest location.