But the US also faced criticism by a human rights group.
The US State Department's annual report on human rights in 2004 provided the latest forum for US criticism of the two Middle East countries that have come into Washington's sights over a number of issues.
The US administration, which has turned up the heat on Damascus since the 14 February assassination of former Lebanese prime minister Rafiq al-Hariri in Beirut, on Monday labelled Syria's rights performance as poor.
It said the government had barred organised political opposition and been responsible for "continuing serious abuses", including torture, arbitrary arrests and prolonged detention without trial.
But Amnesty International thinks America should deal with its own human rights violations first.
Nicole Choueiry, Amnesty's spokeswoman for the Middle East and North Africa, told Aljazeera.net: "Human rights abuses in Iran and Syria are not a new thing.
"We have been condemning the US for its systematic abuse in Abu Ghraib, in Afghanistan and in Iraq. The US needs to look at its own records before it condemns others"
Nicole Choueiry, Amnesty International
"We have been reporting on them for the past 10-20 years, but for the past few years we have also been reporting on human rights violations by the United States.
"We have been condemning the US for its systematic abuse in Abu Ghraib, in Afghanistan and in Iraq. The US needs to look at its own records before it condemns others. Amnesty International condemns the human rights violations of all three countries."
The US report said the Syrian government, "significantly restricted freedom of speech and of the press."
"The government also severely restricted freedom of assembly and association," the report said.
"The [Syrian] government significantly restricted freedom of speech and of the press ... freedom of assembly and association"
US State Department report
The department rebuked the Syrians for limiting freedom of religion and movement, and discriminating against women and the stateless Kurdish minority in the country.
It also cited the Syrian presence in Lebanon as a factor in that country's human rights problems, including arbitrary detentions and the use of excess force by members of the security forces.
The US has demanded the withdrawal of Syria's 14,000 troops from Lebanon, intensifying the call since the assassination of al-Hariri.
It has also urged Damascus to end what the US says is support for fighters in neighbouring Iraq as well as those seeking to derail efforts to make peace between the Israelis and Palestinians.
The State Department report said human rights abuses in Iran had worsened in 2004, with abuses including summary executions, disappearances, torture and other severe punishments such as amputations and flogging.
"The government infringed on citizens' privacy rights and restricted freedom of speech, press, assembly, association, and religion," it said, adding that opposition politicians were harassed, prosecuted, and threatened with jail.
The US says President Muhammad
Khatami's (R) Iran is repressive
The US, which is trying to shut off Iran's suspected nuclear weapons programme, has more recently raised the tone over Tehran's alleged ties to terrorism and its domestic rights record.
"I think there's a broader recognition on the part of the international community that the concerns are not only about their pursuit of nuclear weapons, but their treatment of their own people and their support for terrorism," White House spokesman Scott McClellan said on Monday.