Human Rights Watch has urged the European Union to step up pressure on Iran to take strong steps to end what it says is torture and ill-treatment of detainees and restore freedom of expression.
Human Rights Watch (HRW) said on Monday in a statement announcing a report on the treatment of political prisoners in Iran that the dialogue between the EU and Iran on human rights - which is entering its third year - has failed to achieve any tangible results.
"In fact, the human rights situation in Iran has markedly deteriorated since the inception of the dialogue," Human Rights Watch said in a statement.
"The European Union's weak response to continuing human rights violations in Iran is deeply disturbing," said Sarah Leah Whitson, executive director of Human Rights Watch's Middle East and North Africa Division.
She called upon the EU to condemn what she said was "Iran's record of persecution and torture" and to set "real benchmarks" the government must meet.
Iran's constitution outlaws the use of torture of detainees, but human rights groups say the Islamic Republic's security forces routinely use it to extract confessions.
Human Rights Watch said in a report that Iran "has intensified its campaign of torture, arbitrary arrests and detention against political critics", despite parliament passing legislation to ban torture.
HRW said the report provides an account of the treatment of political detainees in Tehran's Evin Prison and in secret prisons around the capital "since the government launched its current crackdown in 2000".
HRW said the report - based on interviews with journalists, writers and student activists - documents systematic abuse against political detainees, including arbitrary arrest, detention without trial, torture to extract confessions and prolonged solitary confinement.
The report also denounced what it said was the role of plainclothes intelligence agencies, which often operate outside the government structure and report directly to Iran's religious leadership.