20 December 2011 :

Amnesty International said in a report Iran has launched "a killing spree of staggering proportions."
According to the report, at least 600 people were executed in Iran from the beginning of 2011 up to the end of November, of which a minimum of 488 executions were carried out for alleged drug offences.
Amnesty International said the figures showed a threefold increase in comparison to drug-related executions it documented in 2009 (166 executions) and 2010 (172 executions).
"These included reports of secret mass executions at Vakilabad Prison in Mashhad, with one - on 4 August 2010 - involving over 89 individuals."