A statement signed by 225 activists and faxed to The Associated Press in Damascus on Wednesday called for the immediate release of legislators Riyadh Seif and Mamoun Homsi, who were arrested in a crackdown on so-called political "salons" - gatherings in private homes to discuss politics.
The two lawmakers were stripped of their parliamentary immunity and sentenced to five years in prison in 2001.
The statement was issued as Baath Party members met in Damascus for the third day of a conference touted as decisive to the process of reform in a nation under mounting international pressure.
Seif and Homsi were among 10 men sentenced to prison terms ranging from two to 10 years on charges of inciting rebellion, spreading false information and weakening national unity. Four of the 10 have already been released.
The salons sprang up after Syrian President Bashar al-Assad took office in 2000 and began to ease the totalitarian rule of his late father, Hafez al-Assad, a period that came to be known as the "Damascus Spring".
"Spring comes this year as previous years, grim, after it had bloomed in the year 2001," said the activists' statement. "But the forces of oppression ... cracked down on it and extinguished the spirit of life, light and freedom."
Wednesday's statement also called for the release of Ali Abd Allah, a human rights activist who was arrested last month along with eight others for reading out a statement by the banned Muslim Brotherhood at a salon meeting.
"But the forces of oppression ... cracked down on it and extinguished the spirit of life, light and freedom"
The eight were later released but Abd Allah remains in prison.
The statement appealed for the release of all political prisoners in Syria, more freedoms and the return of all political exiles.
Akram al-Bunni, a Syrian writer and reformer who is among the signatories, said anyone hoping for the Baath congress to produce political reforms would be disappointed.
"One cannot hope for reforms, changes or real solutions to the ills of the Syrian society as long as the one-party tutelage over politics and society continues," he wrote in Wednesday's edition of the pan-Arab Al Hayat daily.
In his opening speech to the congress on Monday, al-Assad spoke of the need for economic reforms but did not mention political reforms, dashing the hopes of reformers for serious initiatives that would improve conditions in this autocratic state.
Party members did, however, discuss the legalisation of new political parties and press laws in an effort to open up the country.
The congress does not have the authority to change laws but will issue guidelines and recommendations that the government may or may not use to amend legislation.
Bashar al-Assad is said to have
liberalised some laws
On Tuesday, Vice-President Abd al-Halim Khaddam announced he was stepping down to make way for younger leaders, a move some saw as a sign of serious disagreements within the Syrian political class.
Khaddam helped consolidate Syria's control over Lebanon over the last three decades, though his influence has waned in recent years.
was forced to pull its troops out of Lebanon
in April following the 14 February assassination of former Lebanese Prime Minister Rafiq al-Hariri, for which the Lebanese opposition blamed Syria
and its Lebanese allies.
Both denied any involvement. Besides Khaddam, several others in the 21-member regional command - the Syrian party's highest authority - are likely to resign including Mustafa Tlass, the former defence minister, and Abd Allah al-Ahmar, the party's assistant secretary-general.
The party may also introduce structural changes by decreasing the number of members of the command to 17 and naming new members. Among the expected newcomers is Maher al-Assad, the president's younger brother and member of the Republican Guard.