Iranian authorities restored access to Instgram on Saturday and staged more pro-government rallies in response to nationwide protests that roiled the country last week.

The photo-sharing service and the messaging app Telegram were blocked after the protests against high prices escalated into calls for leadership change. Twitter and Facebook were already banned in Iran.

The protests began just days before Iran marks the 40th anniversary of the start of the revolution that deposed the shah, Mohammad Reza Pahlavi, and led to the creation of the Islamic Republic with Ayatollah Ruhollah Khomeini as supreme leader.

Iran's state TV on Saturday showed pro-government rallies in several cities, starting with Amol, in the northern province of Mazandaram, where hundreds of people waved the Iranian flag and chanted slogans against the United States and Israel.

The rallies, which state TV described as a "response to rioters and supporters of the riots", were meant to be a show of force against protests that broke out in Mashhad, Iran's second largest city, on December 28 and spread to other cities and towns.

At least 21 people were killed and hundreds arrested over the protests, which saw chants against the government of president Hassan Rouhani and the Khomeini's sucessor, Ayatollah Ali Khamenei.

Member of parliament Mahmoud Sadeghi said the whereabouts of around 10 of the 90 university students arrested during the protests were not known. He said about 58 of the students were arrested in Tehran, while some of those detained had not participated in protests and were arrested at home