Several Iranians who protested in Iran over the past few days have spoken to CNN about seeing enormous crowds as well as brutal violence on the streets of Tehran, with one woman saying she saw “bodies piled up on each other” in a hospital.

Protests in Iran are intensifying due to the country's struggling economy, putting pressure on its theocracy as it has shut down the internet and telephone networks.

Iran's Revolutionary Guards warned on Saturday that safeguarding security was a "red line" and the military vowed to protect public property, as the clerical establishment stepped up efforts to quell the most widespread protests in years.

The president has said he will be “hitting them very hard” if Iranian leaders kill protesters amid widespread demonstrations calling for wholesale changes in the country.

In exile for nearly 50 years, Iran's Crown Prince Reza Pahlavi has issued calls urging Iranians to join protests sweeping the country. But support for him may not be clear cut.

New videos posted online after nightfall purport to show fresh protests in a number of areas across Iran. The new protests appear to be taking place in several neighborhoods in the capital Tehran, as well as other cities, including Rasht in the north, Tabriz in the northwest and Shiraz and Kerman in the south.