VIENNA — On the eve of talks to conclude a landmark nuclear deal with Iran, the Obama administration Thursday identified the Tehran government as one of the world’s worst abusers of human rights.

In its annual report on human rights around the world, the State Department cited the theocratic government for depriving its citizens of a range of freedoms, including the right to choose their leaders through free elections. The report portrayed the Iranian justice system as harsh and arbitrary, particularly in cases involving the government’s political opponents, and said senior officials do not punish officials who commit abuses.

Some of the most serious abuses in the past year grew from the government’s disregard for the physical safety of citizens, “whom authorities arbitrarily and unlawfully detained, tortured or killed,” the report said.

Iran was among a handful of countries singled out by Secretary of State John F. Kerry in an introduction to the report. The department also criticized the rights records of Cuba, Myanmar and Vietnam, countries with which the administration is trying to improve relations.

Cuba’s government was cited for harassment of political opponents, a lack of free speech, intimidation and abusive detentions. The report also said that Russia has become increasingly authoritarian and has moved to deny free speech.

Many of the abuses alleged in the report had been cataloged by the State Department in past years’ reports. But this year’s volume has had more visibility than normal because of the nuclear negotiations with Iran.

The report was supposed to have been released Feb. 25. The administration’s critics had charged that the State Department was delaying its release to avoid provoking Iran and possibly hurting prospects for a nuclear deal.

State Department officials have said the release was delayed because of the hectic travel schedule of the secretary, who customarily is present at the report’s release to give it visibility.

Sen. Ted Cruz, R-Texas, a presidential hopeful, had proposed fining the State Department for further delays.

Without identifying him by name, the report cited the case of Washington Post reporter Jason Rezaian, a dual U.S.-Iranian citizen, who was imprisoned last July in Iran and is now on trial on unspecified charges. Rezaian has been denied legal representation and U.S. consular help and is at risk because of health problems and psychological stress, the report said.