"Today there is an unprecedented attack against activists in general and cyber activists in particular," said Hisham al-Miraat, advocacy director at the Global Voices, an international network of bloggers, translators and citizen journalists.
Miraat was speaking at the end of four-day meeting in the Jordanian capital to discuss the challenges they face, including surveillance and censorship.
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"Regimes and their supporters realized after the start of the Arab Spring that the Internet is threat to them. A lot of efforts are being made to introduce oppressive laws, impose censorship and restrict freedom online."
Miraat cited software developer Bassel Safadi, who was jailed in Syria in 2012, and Alaa Abdel Fattah, currently in detention in Egypt for allegedly taking part in a violent and illegal protest in November.
"They have been silenced. Not because they committed a crime, but because their existence is dangerous to these regimes," Miraat.
Bloggers and social media activists from across the Middle East and North Africa met at the Fourth Arab Bloggers Summit to "debate and develop new strategies to deal with the rising challenges," organizers said in a statement.
They also discussed ways to boost cyber activism, digital security, as well as combat censorship and surveillance.
"Challenges now are more difficult and different," said Mohammad al-Gohary, an Egyptian blogger.
"Arab governments know now that cyber activists can create change, so now there is more surveillance. We have to be prepared to face these challenges."
'Bloggers are part of society'
Gohary and Leila Nachawtai, a media coordinator, hinted at divisions among the activists.
"Three years ago, we had clearer and common objectives" of bringing freedom and democracy to the region. "Now the focus is on domestic problems," Nachawtai told AFP.
"This summit came to fight divisions among. We have one goal, to fight dictatorships for the sake of freedoms, particularly freedom of expression. Bloggers are part of society, and the society faces a lot of pressures, but I am optimistic."
Gohary agreed, saying "Internet activists were more organized and had a clearer vision before the Arab Spring."
Many in the region maintain that social media helped keep up the momentum of the protests that began in Tunisia in late 2010, toppling dictators there and in Egypt and Libya, and continue to shake the region.
"Freedoms have dangerously retreated following the beginning of the Arab revolts," Moroccan rapper and activist Muaz Bhagwat told AFP.
Described as "the spiteful" on Facebook and YouTube, Bhagwat said he was jailed twice in 2012 and 2013 because wrote a song "against the regime."
A statement by the organizers has said "the dire state of the region - and the increasingly central role that the Internet and social media are playing in shaping it - has added greater urgency to the summit."
"Dictatorships now know they can silence an important voice by controlling cyber activists," Syrian blogger Marcell Chehwaro told AFP.
"At the beginning of the Arab Spring, we thought that we would restore our freedom of expression. We were wrong."