Iran on Sunday hanged 29 people convicted of drug trafficking, murder and rape in the notorious Tehran prison of Evin, the state broadcaster reported on its website.
The executions, the largest mass execution in the Islamic republic in recent years, were carried out at 5.10 a.m. (0040 GMT).
The latest hangings bring to at least 155 the number of executions carried out in Iran this year, according to an AFP count.
Amnesty International reported that in 2007 Iran applied the death penalty more often than any other country apart from China, executing 317 people during the year.
Capital offences in the Islamic republic include murder, rape, armed robbery, drug trafficking and adultery.
Human rights groups have accused Iran of making excessive use of the death penalty but Tehran insists it is an effective deterrent that is carried out only after an exhaustive judicial process.