The watchdog Reporters Without Borders on Wednesday urged Oman to release bloggers arrested last month for having demanded political reforms in the country which was hit by a wave of protests in 2011.
"We are concerned about the crackdown on Oman's bloggers aimed at silencing the protest movement that has resurfaced in the sultanate, as well as its websites," said the Paris-based RSF.
"We deplore the illegal and random nature of these arrests. We ask the authorities to release the bloggers immediately and unconditionally and to call a halt to arbitrary arrests," it said in a statement.
According to the group, blogger Esmaeel al-Meqbali, a member of the Oman Group for Human Rights, was arrested along with two other activists, Habiba al-Hinai and Yaqoub al-Kharusi on May 31.
They appeared in court on June 4, and were charged with "inciting the crowd" to demonstrate against the government. Hinai and Kharusi were released the same day but Meqbali remained in detention for another week, said RSF.
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Another blogger and activist Eshaq al-Aghbari was arrested on June 4. Two days later, Khalfan al-Badwawi, an engineer and blogger who was one of the organisers of protests last year, was also arrested.
A further wave of arrests took place on June 8, the watchdog said.
Among those held were bloggers Nabhan al-Hinshi and Hassan al-Raqishi, the writer Humood al-Rashdi, the poet Hamad al-Kharousi and two poets and activists, Ali al-Saediand Ali al-Hajji, it added.
On Tuesday, Omani police peacefully dispersed a demonstration in Muscat by a small group of people demanding the release of more than 30 rights activists arrested in past days for demanding reforms.
Civil society groups in the Gulf states had called on Oman to immediately release the rights activists.
The Gulf Forum for Civil Societies, an organisation of liberal activists in the Gulf, said Omani authorities arrested 22 activists on Monday who were demanding the release of 10 others detained the previous week.
Oman was hit by a wave of protests last year demanding political reforms and riot police dispersed the demonstrations with force, killing several activists and arresting many others.