Syrian state TV says the authorities have released 755 people detained during the nine-month-old uprising against President Bashar al-Assad.
The prisoners had been involved “in recent incidents” but their “hands were not stained with blood”, a report said.
The UN says more than 14,000 people are in detention and 5,000 have been killed as a result of the state’s crackdown.
All detained protesters should be freed under a peace plan of the Arab League, whose monitors are now visiting Syria.
The head of the observer mission earlier described the situation in the restive central city of Homs as “reassuring”.
The comments came despite reports that security forces had used live fire to disperse tens of thousands of protesters on Tuesday.
The state TV news flash announcing the prisoner release on Wednesday said only that those affected “did not have Syrian blood on their hands”. It did not mention where the protesters were arrested or detained.
In November, the government announced that it had freed 1,180 prisoners, citing similar conditions.
But earlier this month, UN High Commissioner for Human Rights Navi Pillay said tens of thousands of people had been arrested and more than 14,000 were reported to be in detention as a result of the crackdown.
Human rights activists believe as many as 40,000 people are being held.
Ms Pillay also said she had evidence that Syrian security forces had committed crimes against humanity against the civilian population, including acts of killings, torture, rape and other forms of sexual violence, imprisonment, or other forms of severe deprivation of liberty and enforced disappearances.
On Tuesday, Human Rights Watch accused the Syrian authorities of hiding hundreds of detainees in military installations, which the observers are not permitted to visit.
A Syrian security officer in Homs told the New York-based group that after the government signed the Arab League protocol authorising the observer mission, between 400 and 500 prisoners were moved out of his facility to other places of detention, including at a nearby missile factory.
“Syria’s subterfuge makes it essential for the Arab League to draw clear lines regarding access to detainees, and be willing to speak out when those lines are crossed,” said Sarah Leah Whitson, Human Rights Watch Middle East director.
The BBC’s Jim Muir in neighbouring Lebanon says Wednesday’s prisoner release announcement is a relatively small gesture by the government to give the appearance that it is co-operating with the Arab League.
The Arab League monitors were in Homs again on Wednesday, and three other centres of unrest – the nearby city of Hama, the north-western province of Idlib, and the southern province of Deraa, where the uprising began.
Videos posted on the internet from Homs on Wednesday showed protesters running for cover amid the sound of repeated gunfire.
One resident of the Baba Amr district told Reuters that activists had refused to meet the monitors because they would not give up their Syrian army escort.
On Tuesday, Syrian security forces, which had reportedly been pounding several residential areas in Homs with artillery, eased off before the observers arrived and pulled some tanks off the streets.
But when tens of thousands of protesters took to the streets, tear gas and live fire were used to disperse them, despite the fact that under the peace plan, all military forces are supposed to be withdrawn and peaceful demonstrations permitted.
Activists said security forces killed at least 16 people across Syria on Tuesday, including six in Homs. One group, the Local Co-ordination Committees, put the death toll at 42, including 17 in Homs and seven in Hama.
Despite the reported violence, the head of the observer mission, Sudanese Gen Mustafa al-Dabi, told the Reuters news agency on Wednesday: “The situation seemed reassuring so far.
“There were some places where the situation was not good,” he said. “But there wasn’t anything frightening, at least while we were there. Things were calm and there were no clashes.
“We did not see tanks but we did see some armoured vehicles.”
Our correspondent says Gen Dabi was clearly reserving judgement, as the mission has only just begun and there is still a lot of ground to cover.
Photo: An image grab taken from a video uploaded on YouTube shows Syrian army tanks in the background as a group of Arab League observers tour the flashpoint central city of Homs on December 27, 2011. AFP/Getty Images