Amnesty International called on Iraq Tuesday to stop executions, saying many death sentences were being handed down in court proceedings that do not meet international standards for fair trials.
The human rights groups said Iraq was believed to have at least 1,000 people on death row, including 150 people who had exhausted all legal means to stop their executions and faced hanging.
In a report, the group said the Iraqi government lacked transparency about the executions it has carried out.
Iraq has never released total figures on executions. Amnesty said it had counted 194 executions since the death penalty was reinstated in August 2004.
"However, Amnesty International believes the figures could be much higher, given the secrecy that surrounds these executions and the lack of public information around them," the group said in a statement.
Deputy Justice Minister Busho Ibrahim said he could not comment about the figures cited by the group, but he defended executing people convicted for "terrorist attacks against innocent and civilian victims in markets or in mosques."
He added, "If the terrorists are sentenced to death in a fair trial, then the law should be implemented in order to protect the lives of the people."
Amnesty said that many of the trials did not meet international standards and that some defendants have complained they were tortured into making confessions later used in their trials.
"Many of the death sentences were handed down following court proceedings which did not meet international standards for fair trials, as international human rights law requires," the report said.
Amnesty also said that the death penalty had failed to prevent attacks around the country. Deadly bombings, shootings and sectarian killings have left thousands of people dead since the U.S. invasion in 2003.
The most highly publicized execution carried out in Iraq in recent years was the December 2006 hanging of Saddam Hussein. He was given the death penalty after being convicted for his role in the killing of Shiite Muslims in the town of Dujail after an assassination attempt in 1982.
"Saddam used to kill or bury people alive without any trial, and no organization was willing to talk about this then. I see no reason to preserve the lives of convicted terrorists who have killed whole Iraqi families without reason," Ibrahim said.