Abd al-Rahman al-Shaghuri, 32, was arrested in February 2003 for emailing articles lifted from a British-based website containing articles by Syrian opposition groups that are banned in Syria.
Anwar al-Bunni, a lawyer and member of the Human Rights Association in Syria, told reporters on Sunday that the sentence, imposed by a panel of military and civilian judges, was "a political decision that quells the right of expression in Syria ... and aims at keeping the Syrian society backward".
On Friday, the London-based human rights watchdog Amnesty International urged Syria to release al-Shaghuri and four other detainees who it said were detained for expressing themselves on the internet. Al-Bunni is defending all five of them.
Muhannad and Haytham Qutaysh, who are brothers, and Yahia al-Aws, have been in detention for more than 18 months on charges of sending false information that threatens state security to an electronic newspaper abroad.
Amnesty International has urged
Syria to release the detainees
Their trial before the State Security Court is scheduled for 25 July. Masud Hamid has been held since July 2003 for posting on the internet photographs of a Kurdish demonstration in Damascus.
The Human Rights Association in Syria has urged Interior Minister Ali Hammud not to accept the court's decision but to order the immediate release of al-Shaghuri and the others. State Security Court decisions cannot be appealed against.
Since he came to power in 2000, Syrian President Bashar al-Asad has passed laws aimed at liberalising the state-controlled economy and has introduced cellular phones and the internet.
But he has clamped down on pro-democracy activists, showing there are limits to the dissent that his administration is willing to tolerate. State-run media remains tightly controlled and the government bans websites deemed suspicious or offensive.