Human rights group Amnesty International condemned a violent crackdown by Syrian security forces against a peaceful protest held in Damascus by people calling for the release of political prisoners.
Wednesday's silent protest in which about 150 people had raised pictures of their missing friends and relatives had barely started before plainclothes security forces charged the demonstrators with batons and beat them.
Witnesses told the rights group at least 30 people were arrested, some of whom included family members of political prisoners and human rights activists, and taken to unknown locations. They said security forces beat children, women and the elderly.
"The Syrian authorities must immediately release all those arrested in the last two days for merely attending peaceful protests, and stop these attacks on freedom of expression and assembly," said Philip Luther, Amnesty International's deputy director for the Middle East and North Africa.
Amnesty said several people were also arrested in protests on Tuesday in Damascus and Aleppo, adding at least two people had apparently been released.
Similarly, rights group Human Rights Watch called for the immediate release of all detainees from Wednesday’s protests.
The right of Syrian citizens to assemble in a peaceful manner and speak freely should be respected, Human Rights Watch said.
Sarah Leah Whitson, Middle East director at Human Rights Watch said that "President Bashar al-Asad's recent calls for reform ring hollow when his security services still beat and detain anyone who actually dares to call for reform.”
Wednesday's protest was the most serious demonstration against Syrian President Bashar al-Assad's rule since revolts in the Arab world toppled the Tunisian and Egyptian leaders and led to protracted bloody confrontations in Libya, Bahrain and Yemen.
Syrian authorities, which Human Rights Watch says were among the worst violators of human rights in 2010, have intensified a long-running campaign of arrests of dissidents, independent writers and opposition figures since the Arab mass uprisings.
Assad's Baath Party took power in 1963, banning all opposition and imposing emergency law still in force. There are an estimated 3,000-4,000 political prisoners in Syria, mostly held without trial.