Iranian authorities are pivoting from a ceasefire with Israel to intensify an internal security crackdown across the country with mass arrests, executions and military deployments, particularly in the restive Kurdish region, officials and activists say.

Within days of Israel's airstrikes beginning on June 13, Iranian security forces started a campaign of widespread arrests accompanied by an intensified street presence based around checkpoints, sources have told CBC and Reuters.

One man in Tehran, who responded to a CBC News callout via WhatsApp but did not provide his name, said Wednesday that security officers are stopping people at pop-up checkpoints around the city and asking them to show their phones and open their messaging apps.
"It will take you only one tweet or one social network post to be arrested if the content is believed sensitive by the state," he said.

Another man told CBC he feels "a deep sense of fear" that Ayatollah Ali Khamenei and his regime may have secured their survival and will turn their anger inward as they did in the 1980s, with crackdowns on their own people and mass executions.