A prominent American-Syrian blogger and activist was arrested at the weekend while she was crossing the Jordanian-Syrian border.

Razan Ghazzawi, an outspoken critic of the Assad regime, was detained by Syrian authorities on her way to a conference on media freedom in Amman, Reuters reported.

"She was arrested as she presented her passport to immigration at the Syrian border post of Nassib to cross into Jordan," one of her friends said.

Ghazzawi, who posts under her real name, had recently been campaigning for the release of another blogger, Hussein Ghrer, who was freed Thursday after more than 30 days in prison.

Friends and supporters, who are now managing her Twitter account, have launched an online campaign calling for people to contact politicians and American embassies around the world.

#FreeRazan has gone viral on Twitter over the past few hours, calling for an immediate release of the activist.

Before her arrest, Ghazzawi tweeted: "If anything happens to me, remember that the regime does not fear the prisoners but those who do not forget them."

Fellow activists and bloggers were quick to rally support for Ghazzawi. "Almost every Tweet on my timeline now contains #FreeRazan. You hear us Syrian police? #FREERAZAN," wrote fellow blogger Syrian Sasa.

American-Egyptian blogger Mona El-Tahawy, who was arrested a fortnight ago and allegedly sexually assaulted by the state's riot police, shouted her support on the popular social network: "A very loud #FreeRazan: Razan Ghazawi, activist and courageous #Syrian revolutionary. Arrested today."

American blogger Jillian C. York, director of the International Freedom of Expression at the Electronic Frontier Foundation, angrily wrote on her blog: "I am really fu*king tired of seeing my good friends, one by one, arrested by hideous regimes... the sh*tstorm that I witnessed tonight, the hatred I saw toward Razan simply for exercising her right to free expression, a universal right, instils new anger in me."

The Syrian Centre for Media and Freedom of Expression, of which Ghazzawi was a representative, firmly condemned the arrest.