Huge anti-government protests in Tehran and other Iranian cities, videos show

Huge crowds of protesters have been marching through Iran's capital and other cities, videos show, in what is said to be the largest show of force by opponents of the clerical establishment in years. The peaceful demonstrations in Tehran and the second city of Mashhad on Thursday evening, which were not dispersed by security forces, can be seen in footage verified by BBC Persian. Later, a monitoring group reported a nationwide internet blackout. Protesters can be heard in the footage calling for the overthrow of Iran's Supreme Leader Ayatollah Ali Khamenei and the return of Reza Pahlavi, the exiled son of the late former shah, who had urged his supporters to take to the streets.  It was the 12th consecutive day of unrest that has been sparked by anger over the collapse of the Iranian currency and has spread to more than 100 cities and towns across all 31 of Iran's provinces, according to human rights groups. The US-based Human Rights Activist News Agency (HRANA) has said at least 34 protesters - five of them children - and eight security personnel have been killed, and that 2,270 other protesters have been arrested. Norway-based monitor Iran Human Rights (IHR) has said at least 45 protesters, including eight children, have been killed by security forces. BBC Persian has confirmed the deaths and identities of 22 people, while Iranian authorities have reported the deaths of six security personnel. The protests are seen as the biggest since 2009, when millions of Iranians took to the streets of major cities after a disputed presidential election. Dozens of opposition supporters were killed and thousands were detained in the ensuing crackdown. On Thursday evening, videos posted on social media and verified by BBC Persian showed a large crowd of protesters moving along a major road in Mashhad, in the country's north-east. Chants of "Long live the shah" and "This is the final battle! Pahlavi will return" can be heard. And at one point, several men are seen climbing on an overpass and removing what appears to be surveillance cameras attached to it. Another video posted online showed a large crowd of protesters walking along a major road in eastern Tehran. In footage sent to BBC Persian from the north of the capital, another large crowd is heard chanting "This is the final battle! Pahlavi will return". Elsewhere in the north, protesters were filmed shouting "Dishonourable" and "Don't be afraid, we are all together" following a clash with security forces.