TEHRAN (AFP) - Iran on Wednesday hanged nine people convicted of murder in a mass execution in a Tehran prison as well as a drug trafficker in the north of the country, the Fars news agency reported. The Islamic republic has stepped up its use of the death penalty in an unprecedented crackdown to improve security in society, triggering protests from Western right groups. Fars said that eight men and a woman were executed in Tehran's Evin prison, without giving further details. But Etemad Melli newspaper said that the woman convict, identified only as 30-year-old Tayebeh, was convicted of murdering her seven-year-old stepdaughter. At her final hearing, Tayebeh had retracted an early confession that she had buried the girl alive in a park after picking her up from school and spiking her fruit juice with sleeping pills. A convicted drug trafficker, identified only as FS, was executed on Wednesday in a prison in the northern town of Noshahr, Fars said. The hangings have been mostly carried out in Evin prison.