Iranian security forces have killed at least 3,428 protesters in a crackdown on demonstrations, the Norway-based Iran Human Rights (IHR) NGO said on Wednesday, adding that more than 10,000 people had also been arrested.IHR said the jump in its verified toll was due to new information it received from within the Iranian health and education ministries, with at least 3,379 of the killings coming during the height of the protest movement from January 8 to 12.For all the latest headlines, follow our Google News channel online or via the app.The group's director Mahmood Amiry-Moghaddam condemned the “mass killing of protesters on the streets in recent days,” while IHR warned that even the new figure represented an “absolute minimum” for the actual toll.Read more:US begins withdrawing personnel from Qatar’s Al-Udeid as Iran tensions rise