Libya improved the political rights of its citizens significantly in 2012 by holding successful elections and Egypt's progress was described as "modest," according to Freedom House, a US-based advocate for spreading democracy.
Tunisia, whose uprising two years ago set off the changes across the region, sustained the political gains made in 2011, the group's survey showed.
But calls for elections and accountable government were often suppressed in other states in the region through arrests, imprisonment and other violent means, the report said, and cited Syria with its "murderous war" as the most violent example.
There were also setbacks for freedom in Iraq, Jordan, Kuwait, Lebanon, Oman and the United Arab Emirates, it said.
"However, there is reason to remain cautiously optimistic about the region's future," the group said in the report, released in Washington on Wednesday, and pointed to elections held in Egypt, Tunisia and Libya post-revolution.
"Moreover, the societal impulse to shake off autocratic rule, pervasive injustice, and rampant corruption has clearly spread from Tunisia, Libya, and Egypt to neighboring countries," it said.
Using criteria around topics such as the electoral process, political pluralism and participation, freedom of expression and the rule of law, Freedom House assigns countries a rating on a scale of one to seven, with one being the most free and seven the least.
Libya was one of the big success stories of 2012, according to the report, which now ranks the North African state as "Partly Free" (4 for political rights and 5 for civil liberties) rather than "Not Free" (7 and 6).
"Having ranked among the world's worst tyrannies for decades, the country scored major gains in 2012, especially in the political rights categories," the report said.
However, Libya suffers because it does not have clear government control over many parts of its territory, a situation exacerbated by local militias and radical Islamists.
The US ambassador and three other Americans were killed in an attack on the diplomatic post in Benghazi last September.Egypt's modest gains
Egypt also moved to "Partly Free" from "Not Free" after the presidential election in June brought Mohamed Mursi to power, which Freedom House described as a "flawed but competitive" poll.
The country still faces significant threats to its democratic gains, however, and suffered some setbacks in 2012, the report said.
It cited what it described as a "faulty process" to draft a new constitution, resistance to change by entrenched elites, a presidential decree which lent Mursi sweeping powers and plans to investigate leading opposition figures on charges of treason.
The rating of Yemen, whose long-serving president Ali Abdullah Saleh handed power to his deputy Abd-Rabbu Mansour Hadi, was unchanged at "Not Free" (6 in both categories). Hadi became president after an uncontested election in February 2012.
The Gulf region continued to see a decline in democratic freedoms, the report said.
Kuwait was rated the most free of the Gulf Arab states and Saudi Arabia the least.
The United Arab Emirates was downgraded due to arrests of people calling for reform, the passing of a "highly restrictive" internet law and the dismissal and deportation of academics who were critical of government policies, the report said.
The UAE has moved swiftly to stem any sign of political dissent by detaining more than 60 local Islamists last year over alleged threats to state security and links to a foreign group.
Bahrain handed out lengthy prison sentences to opposition activists, Freedom House said. Bahrain says it is committed to grant all defendants a fair trial.
Oman lost ground due to the arrests of human rights and reform activists, the report said. Omani authorities have said they are cracking down on the increased use of defamatory statements on social media that threatened security. Its National Human Rights Commission said there had been no violations.
Kuwait's political rights rating declined thanks to its parliamentary crisis - the legislature was dissolved twice in 2012 - and what the report described as attempts to undermine the opposition by revising the electoral law.
Kuwait's government says the law needed to be changed to bring the country in line with democratic electoral systems elsewhere and ensure stability.
KUWAIT (Reuters) -- Countries whose leaders were overthrown in the "Arab Spring" revolts of 2011 mostly made democratic gains in 2012 but the uprisings triggered crackdowns elsewhere in the region, an annual survey of political and civil liberties around the world showed.